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Proving correctness of Timed Concurrent Constraint Programs

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Proving correctness of Timed Concurrent Constraint Programs F.S.de Boer Universiteit Utrecht ?M.Gabbrielli Universit`a di Bologna §M.C.Meo Universit`a di Chieti ?Abstract A temporal logic is presented for reasoning about the correctness of timed concurrent constraint programs.The logic is based on modalities which allow one to specify what a process produces as a reaction to what its environment inputs.These modalities provide an assumption/commitment style of speci?cation which allows a sound and complete compositional axiomatization of the reactive behavior of timed concurrent constraint programs.Keywords :Concurrency,constraints,real-time programming,temporal logic.1Introduction Many “real-life”computer applications maintain some ongoing interaction with external physical pro-cesses and involve time-critical aspects.Characteristic of such applications,usually called real-time embedded systems,is the speci?cation of timing constraints such as,for example,that an input is re-quired within a bounded period of time.Typical examples of such systems are process controllers and signal processing systems.In [5]tccp ,a timed extension of the pure formalism of concurrent constraint programming([25]),is introduced.This extension is based on the hypothesis of bounded asynchrony (as introduced in [27]):Computation takes a bounded period of time rather than being instantaneous as in the concurrent synchronous languages ESTEREL [3],LUSTRE [16],SIGNAL [20]and Statecharts [17].Time itself is measured by a discrete global clock,i.e,the internal clock of the tccp process.In [5]we also introduced timed reactive sequences which describe at each moment in time the reaction of a tccp process to the input of the external environment.Formally,such a reaction is a pair of constraints c,d ,where c is the input given by the

environment and d is the constraint produced by the process in response to the input c (such a response includes always the input because of the monotonicity of ccp computations).

In this paper we introduce a temporal logic for describing and reasoning about timed reactive sequences.The basic assertions of the temporal logic describe the reactions of such a sequence in terms of modalities which express either what a process assumes about the inputs of the environment and what a process commits to,i.e.,has itself produced at one time-instant.These modalities thus provide a kind of as-sumption/commitment style of speci?cation of the reactive behavior of a process.The main result of this paper is a sound and complete compositional proof system for reasoning about the correctness of tccp programs as speci?ed by formulas in this temporal logic.

The remainder of this paper is organized as follows.In the next section we introduce the language tccp and its operational semantics.In Section 3we introduce the temporal logic and the compositional proof system.In Section 4we discuss soundness and completeness of the proof system.Section 5concludes by discussing related work and indicating future research.A preliminary,short version of this paper appeared in [7].

2The programming language

In this section we?rst de?ne the tccp language and then we de?ne formally its operational semantics by using a transition system.

Since the starting point is ccp,we introduce?rst some basic notions related to this programming paradigm.We refer to[26,28]for more details.The ccp languages are de?ned parametrically wrt to a given constraint system.The notion of constraint system has been formalized in[26]following Scott’s treatment of information systems.Here we only consider the resulting structure.

De?nition2.1A constraint system is a complete algebraic lattice C,≤,?,true,false where?is the lub operation,and true,false are the least and the greatest elements of C,respectively.

Following the standard terminology and notation,instead of≤we will refer to its inverse relation,denoted by?and called entailment.Formally,?c,d∈C.c?d?d≤c.In order to treat the hiding operator of the language a general notion of existential quanti?er is introduced which is formalized in terms of cylindric algebras[18].Moreover,in order to model parameter passing,diagonal elements[18]are added to the primitive constraints.This leads to the concept of a cylindric constraint system.In the following, we assume given a(denumerable)set of variables Var with typical elements x,y,z,....

De?nition2.2Let C,≤,?,true,false be a constraint system.Assume that for each x∈Var a function ?x:C→C is de?ned such that for any c,d∈C:

(i)c??x(c),(ii)if c?d then?x(c)??x(d),

(iii)?x(c??x(d))=?x(c)??x(d),(iv)?x(?y(c))=?y(?x(c)).

Moreover assume that for x,y ranging in Var,C contains the constraints d xy(so called diagonal elements) which satisfy the following axioms:

(v)true?d xx,(vi)if z=x,y then d xy=?z(d xz?d zy),

(vii)if x=y then d xy??x(c?d xy)?c.

Then C= C,≤,?,true,false,Var,?x,d xy is a cylindric constraint system.

Note that if C models the equality theory,then the elements d xy can be thought of as the formulas x=y. In the sequel we will identify a system C with its underlying set of constraints C and we will denote?x(c) by?x c with the convention that,in case of ambiguity,the scope of?x is limited to the?rst constraint sub-expression(so,for instance,?x c?d stands for?x(c)?d).

The basic idea underlying ccp is that computation progresses via monotonic accumulation of information in a global https://www.doczj.com/doc/5815017866.html,rmation is produced by the concurrent and asynchronous activity of several agents which can add(tell)a constraint to the store.Dually,agents can also check(ask)whether a constraint is entailed by the store,thus allowing synchronization among di?erent agents.Parallel composition in ccp is modeled by the interleaving of the basic actions of its components.

When querying the store for some information which is not present(yet)a ccp agent will simply suspend until the required information has arrived.In timed applications however often one cannot wait indef-initely for an event.Consider for example the case of a bank teller machine.Once a card is accepted and its identi?cation number has been checked,the machine asks the authorization of the bank to release the requested money.If the authorization does not arrive within a reasonable amount of time,then the card should be given back to the customer.A timed language should then allow us to specify that,in case a given time bound is exceeded(i.e.a time-out occurs),the wait is interrupted and an alternative action is taken.Moreover in some cases it is also necessary to abort an active process A and to start a process B when a speci?c event occurs(this is usually called preemption of A).For example,according to a typical pattern,A is the process controlling the normal activity of some physical device,the event indicates some abnormal situation and B is the exception handler.

In order to be able to specify these timing constraints in ccp we introduce a discrete global clock and assume that ask and tell actions take one https://www.doczj.com/doc/5815017866.html,putation evolves in steps of one time-unit, so called clock-cycles.We consider action pre?xing as the syntactic marker which distinguishes a time instant from the next one.Furthermore we make the assumption that parallel processes are executed on di?erent processors,which implies that at each moment every enabled agent of the system is activated. This assumption gives rise to what is called maximal parallelism.The time in between two successive moments of the global clock intuitively corresponds to the response time of the underlying constraint system.Thus essentially in our model all parallel agents are synchronized by the response time of the underlying constraint system.

Furthermore,on the basis of the above assumptions we introduce a timing construct of the form now c then A else B which can be interpreted as follows:If the constraint c is entailed by the store at the current time t then the above agent behaves as A at time t,otherwise it behaves as B at time t.As shown in[5,27]this basic construct allows one to derive such timing mechanisms as time-out and preemption. Thus we end up with the following syntax of timed concurrent constraint programming.

De?nition2.3[tccp Language[5]]Assuming a given cylindric constraint system C the syntax of agents is given by the following grammar:

A::=tell(c)| n i=1ask(c i)→A i|now c then A else B|A B|?xA|p(x)

where the c,c i are supposed to be?nite constraints(i.e.algebraic elements)in C.A tccp process P is then an object of the form D.A,where D is a set of procedure declarations of the form p(x)::A and A is an agent.

Action pre?xing is denoted by→,non-determinism is introduced via the guarded choice construct n i=1ask(c i)→A i,parallel composition is denoted by ,and a notion of locality is introduced by the agent?xA which behaves like A with x considered local to A,thus hiding the information on x pro-vided by the external environment.In the next subsection we describe formally the operational semantics of tccp.In order to simplify the notation,in the following we will omit the n i=1whenever n=1and we will use tell(c)→A as a shorthand for tell(c) (ask(true)→A).In the following we also assume guarded recursion,that is we assume that each procedure call is in the scope of an ask construct.This assumption,which does not limit the expressive power of the language,is needed to ensure a proper de?nition of the operational semantics.

2.1Operational semantics

The operational model of tccp can be formally described by a transition system T=(Conf,?→)where we assume that each transition step takes exactly one time-unit.Con?gurations(in)Conf are pairs consisting of a process and a constraint in C representing the common store.The transition relation ?→?Conf×Conf is the least relation satisfying the rules R1-R10in Table1and characterizes the (temporal)evolution of the system.So, A,c ?→ B,d means that if at time t we have the process A and the store c then at time t+1we have the process B and the store d.

Let us now brie?y discuss the rules in Table1.In order to represent successful termination we introduce the auxiliary agent stop:it cannot make any transition.Rule R1shows that we are considering here the so called“eventual”tell:The agent tell(c)adds c to the store d without checking for consistency of c?d and then stops.Note that the updated store c?d will be visible only starting from the next time instant since each transition step involves exactly one time-unit.According to rule R2the guarded choice operator gives rise to global non-determinism:The external environment can a?ect the choice since ask(c j)is enabled at time t(and A j is started at time t+1)i?the store d entails c j,and d can be modi?ed by other agents.The rules R3-R6show that the agent now c then A else B behaves as A or B depending on the fact that c is or is not entailed by the store.Di?erently from the case of the ask,here the evaluation of the guard is instantaneous:If A,d ( B,d )can make a transition at time t and c is(is not)entailed by the store d,then the agent now c then A else B can make the

R1 tell(c),d ?→ stop,c?d

R2 n i=1ask(c i)→A i,d ?→ A j,d j∈[1,n]and d?c j

A,d ?→ A′,d′

R3

d?c

now c then A else B,d ?→ A,d

B,d ?→ B′,d′

R5

d?c

now c then A else B,d ?→ B,d

A,c ?→ A′,c′ B,c ?→ B′,d′

R7

A B,c ?→ A′ B,c′

B A,c ?→ B A′,c′

A,d??x c ?→ B,d′

R9

p(x),c ?→ B,d p(x)::A∈D

Table1:The transition system for tccp.

same transition at time t.Moreover,observe that in any case the control is passed either to A(if c is entailed by the current store d)or to B(in case d does not entail c).Rules R7and R8model the parallel composition operator in terms of maximal parallelism:The agent A B executes in one time-unit all the initial enabled actions of A and B.Thus,for example,the agent A:(ask(c)→stop) (tell(c)→stop) evaluated in the store c will(successfully)terminate in one time-unit,while the same agent in the empty store will take two time-units to terminate.The agent?xA behaves like A,with x considered local to A,i.e.the information on x provided by the external environment is hidden to A and,conversely,the information on x produced locally by A is hidden to the external world.To describe locality in rule R9 the syntax has been extended by an agent?d xA where d is a local store of A containing information on x which is hidden in the external store.Initially the local store is empty,i.e.?xA=?true xA.

Rule R10treats the case of a procedure call when the actual parameter equals the formal parameter. We do not need more rules since,for the sake of simplicity,here and in the following we assume that the set D of procedure declarations is closed wrt parameter names:That is,for every procedure call p(y)appearing in a process D.A we assume that if the original declaration for p in D is p(x)::A then D contains also the declaration p(y)::?x(tell(d xy) A)1.

Using the transition system described by(the rules in)Table1we can now de?ne our notion of observables

which associates with an agent a set of timed reactive sequences of the form

c1,d1 ··· c n,d n d,d

where a pair of constraints c i,d i represents a reaction of the given agent at time i:Intuitively,the agent transforms the global store from c i to d i or,in other words,c i is the assumption on the external environment while d i is the contribution of the agent itself(which includes always the assumption).The last pair denotes a“stuttering step”in which no further information can be produced by the agent,thus indicating that a“resting point”has been reached.

Since the basic actions of tccp are monotonic and we can also model a new input of the external environ-ment by a corresponding tell operation,it is natural to assume that reactive sequences are monotonically increasing.So in the following we will assume that each timed reactive sequence c1,d1 ··· c n?1,d n?1 c n,c n satis?es the following condition:d i?c i and c j?d j?1,for any i∈[1,n?1]and j∈[2,n].Since the constraints arising from the reactions are?nite,we also assume that a reactive sequence contains only

?nite constraints2.

The set of all reactive sequences is denoted by S and its typical elements by s,s1...,while sets of reactive sequences are denoted by S,S1...andεindicates the empty reactive sequence.Furthermore,·denotes the operator which concatenates sequences.Operationally the reactive sequences of an agent are generated

as follows.

De?nition2.4We de?ne the semantics R∈Agent→P(S)by

R(A)={ c,d ·w∈S| A,c → B,d and w∈R(B)}

{ c,c ·w∈S| A,c →and w∈R(A)∪{ε}}.

Note that R(A)is de?ned as the union of the set of all reactive sequences which start with a reaction of

A and the set of all reactive sequences which start with a stuttering step of A.In fact,when an agent is blocked,i.e.,it cannot react to the input of the environment,a stuttering step is generated.After such a stuttering step the computation can either continue with the further evaluation of A(possibly generating more stuttering steps)or it can terminate,as a“resting point”has been reached.These two case are

re?ected in the second part of the de?nition of R(A)by the two conditions w∈R(A)and w∈{ε}, respectively.Note also that,since the stop agent used in the transition system cannot make any move,

an arbitrary(?nite)sequence of stuttering steps is always appended to each reactive sequence.

Formally R is de?ned as the least?xed-point of the corresponding operatorΦ∈(Agent→P(S))→Agent→P(S)de?ned by

Φ(I)(A)={ c,d ·w∈S| A,c → B,d and w∈I(B)}

{ c,c ·w∈S| A,c →and w∈I(A)∪{ε}}.

The ordering on Agent→P(S)is that of(point-wise extended)set-inclusion(it is straightforward to check thatΦis continuous).

3A calculus for tccp

In this section we introduce a temporal logic for reasoning about the reactive behavior of tccp programs. We?rst de?ne temporal formulas and the related notions of truth and validity in terms of timed reactive sequences.Then we introduce the correctness assertions that we consider and a corresponding proof system.

3.1Temporal logic

Given a set M,with typical element X,Y,...,of monadic constraint predicate variables,our temporal logic is based on atomic formulas of the form X(c),where c is a constraint of the given underlying constraint system.The distinguished predicate I will be used to express the“assumptions”of a process about its inputs,that is,I(c)holds if the process assumes the information represented by c is produced by its environment.On the other hand,the distinguished predicate O represents the output of a process, that is,O(c)holds if the information represented by c is produced by the process itself(recall that the produced information includes always the input,as previously mentioned).More precisely,these formulas I(c)and O(c)will be interpreted with respect to a reaction which consists of a pair of constraints c,d , where c represents the input of the external environment and d is the contribution of the process itself (as a reaction to the input c)which always contains c(i.e.such that d≥c holds).

An atomic formula in our temporal logic is a formula as described above or an atomic formula of the form c≤d which‘imports’information about the underlying constraint system,i.e.,c≤d holds if d?c. Compound formulas are constructed from these atomic formulas by using the(usual)logical operators of negation,conjunction and(existential)quanti?cation and the temporal operators (the next operator) and U(the until operator).We have the following three di?erent kinds of quanti?cation:?quanti?cation over the variables x,y,...of the underlying constraint system;

?quanti?cation over the constraints c,d,...themselves;

?quanti?cation over the monadic constraint predicate variables X,Y,....

Variables p,q,...will range over the constraints.We will use V,W,...,to denote a variable x of the underlying constraint system,a constraint variable p or a constraint predicate X.

De?nition3.1[Temporal formulas]Given an underlying constraint system with set of constraints C, formulas of the temporal logic are de?ned by

φ::=p≤q|X(c)|?φ|φ∧ψ|?Vφ| φ|φUψ

In the sequel we assume that the temporal operators have binding priority over the propositional con-nectives.We introduce the following abbreviations:c=d stands for c≤d∧d≤c,3φfor true Uφand 2φfor?3?φ.We also useφ∨ψas a shorthand for?(?φ∧?ψ)andφ→ψas a shorthand for?φ∨ψ. Finally,given a temporal formulaφ,we denote by F V(φ)(F V constr(φ))the set of the free(constraint)

variables ofφ.

De?nition3.2Given an underlying constraint system with set of constraints C,the truth of an atomic formula X(c)is de?ned with respect to a predicate assignment v∈M→C which assigns to each monadic predicate X a constraint.We de?ne

v|=X(c)if v(X)?c.

Thus X(c)holds if c is entailed by the constraint represented by X.In other words,a monadic constraint predicate X denotes a set{d|d?c}for some c.We restrict to constraint predicate assignments which are monotonic in the following sense:v(O)?v(I).In other words,the output of a process contains its input.

The temporal operators are interpreted with respect to?nite sequenceρ=v1,...,v n of constraint predicate assignments in the standard manner: φholds ifφholds in the next time-instant andφUψholds if there exists a future moment(possibly the present)in whichψholds and until thenφholds.We restrict to sequencesρ=v1,...,v n which are monotonic in the following sense:for1≤i

?v i+1(X)?v i(X),for every predicate X;

?v i+1(I)?v i(O).

The latter condition requires that the input of a process contains its output at the previous time-instant. Note that these conditions corresponds with the monotonicity of reactive sequences as de?ned above.

In order to de?ne the truth of a temporal formula we introduce the following notions:given a?nite sequenceρ=v1,...,v n of predicate assignments,we denote by l(ρ)=n the length ofρandρi=v i, 1≤i≤n.We also de?neρ<ρ′ifρis a proper su?x ofρ′(ρ≤ρ′ifρ<ρ′orρ=ρ′).Given a variable x of the underlying constraint systems and a predicate assignment v we de?ne the predicate assignment ?xv by?xv(X)=?x d,where d=v(X).Given a sequenceρ=v1,...,v n,we denote by?xρthe sequence ?xv1,...,?xv n.Moreover,given a monadic constraint predicate X and a predicate assignment v we denote by?Xv the restriction of v to M\{X}.Given a sequenceρ=v1,...,v n,we denote by?Xρthe sequence?Xv1,...,?Xv n.Furthermore,byγwe denote a constraint assignment which assigns to each constraint variable p a constraintγ(p).Finally,γ{c/p}denotes the result of assigning inγthe constraint c to the variable p.

Moreover,we assume that time does not stop,so actually a?nite sequence v1···v n represents the in?nite sequence v1···v n,v n,v n···with the last element repeated in?nitely many times.Formally,this assumption is re?ected in the following de?nition in the interpretation of the .By a slight abuse of notation,given a sequenceρ=v1···v n with n≥1we de?ne ρas follows

(n=1) v1=v1

(n>1) ρ=v2···v n.

The truth of a temporal formula is then de?ned as follows.

De?nition3.3Given a sequence of predicate assignmentsρ=v1,v2,...,v n,a constraint assignmentγandφa temporal formula,we de?neρ|=γφby:

by:

ρ|=γp≤q ifγ(q)?γ(p)

ρ|=γX(c)ifρ1|=X(c)

ρ|=γ?φifρ|=γφ

ρ|=γφ1∧φ2ifρ|=γφ1andρ|=γφ2

ρ|=γ?xφifρ′|=γφ,for someρ′s.t.?xρ=?xρ′

ρ|=γ?Xφifρ′|=γφ,for someρ′s.t.?Xρ=?Xρ′

ρ|=γ?pφifρ|=γ′φ,for some c s.t.γ′=γ{c/p}

ρ|=γ φif ρ|=γφ

ρ|=γφUψif for someρ′≤ρ,ρ′|=γψand for allρ′<ρ′′≤ρ,ρ′′|=γφ.

Moreoverρ|=φi?ρ|=γφfor every constraint assignmentγ.

De?nition3.4A formulaφis valid,notation|=φ,i?ρ|=φfor every sequenceρof predicate assign-ments.

We have the validity of the usual temporal tautologies.Monotonicity of the constraint predicates wrt the entailment relation of the underlying constraint system is expressed by the formula

?p?q?X(p≤q→(X(q)→X(p))).

Monotonicity of the constraint predicates wrt time implies the validity of the following formula

?p?X(X(p)→2X(p)).

The relation between the distinguished constraint predicates I and O is logically described by the laws

?p(I(p)→O(p))and?p(O(p)→ I(p)),

that is,the output of a process contains its input and is contained in the inputs of the next time-instant.

3.2The proof-system

We introduce now a proof-system for reasoning about the correctness of tccp programs.We?rst de?ne formally the correctness assertions and their validity.

De?nition3.5Correctness assertions are of the form A satφ,where A is a tccp process andφis a temporal formula.The validity of an assertion A satφ,denoted by|=A satφ,is de?ned as follows

|=A satφi?ρ|=φ,for allρ∈R′(A),

where

R′(A)={v1,...,v n| v1(I),v1(O) ··· v n(I),v n(O) ∈R(A)}.

Roughly,the correctness assertion A satφstates that every sequenceρof predicate assignments such that its‘projection’onto the distinguished predicates I and O generates a reactive sequence of A,satis?es the temporal formulaφ.

T1tell(c)sat O(c)∧?p(O(p)→?q(I(q)∧q?c=p))∧ 2stut

A i satφi,?i∈[1,n]

T2

now c then A else B sat(I(c)∧φ)∨(?I(c)∧ψ)

T4A satφ

A B sat?X,Y(φ[X/O]∧ψ[Y/O]∧par(X,Y))X,Y∈F V(φ)∪F V(ψ),X=Y

p(x)satφ?p A satφ

T6

A satψ

Table2:The system TL for tccp.

Table2presents the proof-system.

Axiom T1states that the execution of tell(c)consists of the output of c(as described by O(c))together with any possible input(as described by I(q)).Moreover,at every time-instant in the future no further output is generated,which is expressed by the formula

?p(O(p)?I(p)),

which we abbreviate by stut(since it represents stuttering steps).

In rule T2I i stands for I(c i).Given that A i satis?esφi,rule T2allows the derivation of the speci?cation forΣn i=1ask(c i)→A i,which expresses that either eventually c i is an input and,consequently,φi holds in the next time-instant(since the evaluation of the ask takes one time-unit),or none of the guards is ever satis?ed.

Rule T3simply states that if A satis?esφand B satis?esψthen every computation of now c then A else B satis?es eitherφorψ,depending on the fact that c is an input or not.

Hiding of a local variable x is axiomatized in rule T4by?rst existentially quantifying x inφ∧loc(x),where loc(x)denotes the following formula which expresses that x is local,i.e.,the inputs of the environment do not contain new information on x:

?p(?x p=p→(?I(p)∧2( I(p)→?r(O(r)∧?x p?r=p)))).

This formula literally states that the initial input does not contain information on x and that everywhere in the computation if in the next state an input contains information on x then this information is already contained by the previous output.Finally,the following formula inv(x)

?p2(?x p=p→(O(p)→?r(I(r)∧?x p?r=p)))

states that the process does not provide new information on the global variable x.

Rule T5gives a compositional axiomatization of parallel composition.The‘fresh’constraint predicates X and Y are used to represent the outputs of A and B,respectively(φ[X/O]andψ[Y/O]denote the result of replacing O by X and Y).Additionally,the formula

?p2(O(p)?(?q1,q2(X(q1)∧Y(q2)∧q1?q2=p))),

denoted by par(X,Y),expresses that every output of A B can be decomposed into outputs of A and B.

Rule T6,where?p denotes derivability within the proof system,describes recursion in the usual manner by using a meta-rule(Scott-induction,see also[4]):we can conclude that the agent p(x)satis?es a propertyφwhenever the body of p(x)satis?es the same property assuming the conclusion of the rule. In this rule x is assumed to be both the formal and the actual parameter.We do not need more rules since,as previously mentioned,we can assumed that the set D of procedure declarations is closed wrt parameter names.

Note also that,for the sake of simplicity,we do not mention explicitly the declarations in the proof system.In fact,the more precise formulation of this rule,that will be needed in the proofs,would be the following:

D\{p}.p(x)satφ?p D\{p}.A satφ

4Soundness and completeness

We investigate now soundness and completeness of the above calculus.Here and in the following,in order to clarify some technical details,we consider processes of the form D.A rather than agents of the form A with a separate set of declarations D.All the previous de?nitions can be extended to processes in the obvious way.We also denote by?p D.A satφthe derivability of the correctness assertion D.A satφin the proof system introduced in the previous section(assuming as additional axioms in rule T7all valid temporal formulas).

Soundness means that every provable correctness assertion is valid:whenever?p D.A satφ,i.e.D.A satφis derivable,then|=D.A satφ.Completeness on the other hand consists in the derivability of every valid correctness assertion:whenever|=D.A satφthen?p D.A satφ(in T).

At the heart of the soundness and completeness results that we are going to prove lies the compositionality of the semantics R′,which follows from the compositionality of the underlying semantics R.In order to prove such a compositionality,we?rst introduce a denotational semantics[[D.A]](e)where,for technical reasons,we represent explicitly the environment e which associate a denotation to each procedure iden-ti?er.More precisely,assuming that Pvar denotes the set of procedure identi?er,Env=Pvar→?(S), with typical element e,is the set of environments.

Given a process D.A,the denotational semantics[[D.A]]:Env→?(S)is de?ned by the equations in Table3,whereμdenotes the least?xpoint wrt subset inclusion of elements of?(S).The semantic operators appearing in Table3are formally de?ned as follows.Intuitively they re?ect,in terms of reactive sequences,the operational behaviour of their syntactic counterparts.

De?nition4.1[5]Let S,S i be sets of reactive sequences and c,c i be constraints.Then we de?ne the operators? ,? ,?now and??x as follows:

Guarded Choice

? n i=1c i→S i={s·s′∈S|s= d1,d1 ··· d m,d m ,d j?c i for each j∈[1,m-1],i∈[1,n],

d m?c h and s′∈S h for an h∈[1,n]}

{s∈S|s= d1,d1 ··· d m,d m ,d j?c i for each j∈[1,m],i∈[1,n]},

Parallel Composition Let? ∈S×S→S be the(commutative and associative)partial operator de?ned as follows:

c1,d1 ··· c n,d n d,d ? c1,e1 ··· c n,e n d,d = c1,d1?e1 ··· c n,d n?e n d,d .

We de?ne S1? S2as the point-wise extension of the above operator to sets.

The Now-Operator

now(c,S1,S2)={s∈S|s= c′,d ·s′and either c′?c and s∈S1or c′?c and s∈S2}.

?

The Hiding Operator We?rst need the following notions similar to those used in[8]:

Given a sequence s= c1,d1 ··· c n,c n ,we denote by?xs the sequence ?xc1,?xd1 ··· ?xc n,?xc n .

A sequence s′= c1,d1 ··· c n,c n is x-connected if

??x c1=c1(that is,the input constraint of s′does not contain information on x)and

??x c i?d i?1=c i for each i∈[2,n](that is,each assumption c i does not contain any information on x which has not been produced previously in the sequence by some d j).

A sequence s is x-invariant if

?for all computation steps c,d of s,d=?x d?c holds.

The semantic hiding operator then can be de?ned as follows:

??xS={s∈S|there exists s′∈S such that?

s=?x s′,s′is x-connected and s is x-invariant}.

x

A few explanations are in order here.Concerning the semantic choice operator,a sequence in? n i=1c i→S i consists of an initial period of waiting for(a constraint stronger than)one of the constraints c i.During this waiting period only the environment is active by producing the constraints d i while the process itself generates the stuttering steps d i,d i .Here we can add several pairs since the external environment can take several time-units to produce the required constraint.When the contribution of the environment is strong enough to entail a c h the resulting sequence is obtained by adding s′∈S h to the initial waiting period.

In the semantic parallel operator de?ned on sequences we require that the two arguments of the operator agree at each point of time with respect to the contribution of the environment(the c i’s)and that they have the same length(in all other cases the parallel composition is assumed being unde?ned).

In the de?nition of??we say that a sequence is x-connected if no information on x is present in the input constraints which has not been already accumulated by the computation of the agent itself.A sequence is x-invariant if its computation steps do not provide more information on x.

If D.A is a closed process,that is if all the procedure names occurring in A are de?ned in D,then [[D.A]](e)does not depend on e and will be indicated as[[D.A]].Environments in general allows us to de?ned the semantics also of processes which are not closed,and this will be used in the soundness proof. The following result shows the correspondence between the two semantics we have introduced and there-fore the compositionality of R(A).

Theorem4.2[5]If D.A is closed then R(A)=[[D.A]]holds.

E1[[D.stop]](e)={ c1,c1 c2,c2 ··· c n,c n ∈S|n≥1}

E2[[D.tell(c)]](e)={ d,d?c ·s∈S|s∈[[D.stop]](e)}

E3[[D. n i=1ask(c i)→A i]](e)=? n i=1c i→[[D.A i]](e)

E4[[D.now c then A else B]](e)=?

now(c,[[D.A]](e),[[D.B]](e))

E5[[D.A B]](e)=[[D.A]](e)? [[D.B]](e)

E6[[D.?xA]](e)=??x[[D.A]](e)

E7[[D.p(x)]](e)=μΨ

whereΨ(f)=[[D\{p}.A]](e{f/p}),p(x)::A∈D

Table3:The semantics[[D.A]](e).

In order to prove the soundness of the calculus we have to interpret also correctness assertions about arbitrary processes(that is,including processes which do contain unde?ned procedure variables).

De?nition 4.3Given a underlying constraint system C and an environment e ,we de?ne |=e D.A sat φi?

ρ|=φ,for all ρ∈[[D.A ]]′(e ),

where

[[D.A ]]′(e )={v 1,...,v n | v 1(I ),v 1(O ) ··· v n (I ),v n (O ) ∈[[D.A ]](e )}.

Note that,for closed processes,|=e coincides with |=as previously de?ned.We ?rst need the following Lemma.

Lemma 4.4Let φbe a temporal formula,ρand ρ′be sequences of predicate assignment and let V be a variable such that either V ∈M or V is a variable x of the underlying constraint system.The following holds:

1.Assume that ρ|=φ.Then ρ′|=?V φfor each ρ′such that ?V ρ=?V ρ′.

2.Assume that ρ|=?V φand F V constr (φ)=?.Then there exists ρ′such that ρ′|=φand ?V ρ′=?V ρ.Proof

1.Assume that ρ|=φ.By De?nition 3.3,ρ|=γφfor each γand then for each ρ′such that ?V ρ=?V ρ′,we have that ρ′|=γ?V φfor each γ.Therefore,by De?nition 3.3,ρ′|=?V φ.

2.Assume that ρ|=?V φand F V constr (φ)=?.By De?nition

3.3,ρ|=γ?V φfor each γ.Then by De?nition 3.3,for each γthere exists ρ′such that ?V ρ=?V ρ′and ρ′|=γφ.Since by hypothesis F V constr (φ)=?,whenever ρ′|=γφwe also have that ρ′|=φand then the thesis holds.

The following Theorem is the core of the soundness result.

Theorem 4.5Let us denote D i .A i by P i for 1≤i ≤n and D.A by P .If

P 1sat φ1,...,P n sat φn ?p P sat φand |=e P i sat φi ,

for i =1,...,n ,then

|=e P sat φ.

Proof The proof is by induction on the length l of the derivation.

(l =1)In this case A =tell (c )and ?p D.tell (c )sat O (c )∧?p (O (p )→?q (I (q )∧q ?c =p ))∧ 2stut .By

De?nition 4.3,we have to prove that for any e ,ρ|=O (c )∧?p (O (p )→?q (I (q )∧q ?c =p ))∧ 2stut ,for all ρ∈[[D.tell (c )]]′(e ).By equation E2of Table 3and De?nition 4.3,

[[D.tell (c )]]′(e )={ρ|ρ1(O )=ρ1(I )?c and ρi (O )=ρi (I )for i ∈[2,l (ρ)]}.

The remaining of the proof for this case is straightforward.

(l >1)We distinguish various cases according to the last rule applied in the derivation.

Rule T2.In this case ?p D. n

i =1ask (c i )→A i sat χ,where χis the formula

n i =1

(

n j =1?I (c j )∧stut )U (I (c i )∧stut ∧ φi ) ∨2(n j =1?I (c j )∧stut ).Since for each i ∈[1,n ]the proof D.A i sat φi is shorter than the current one,from the inductive hypothesis follows that,for every environment e and for each i ∈[1,n ],|=e D.A i sat φi ,that is ρ|=φi ,for all ρ∈[[D.A i ]]′(e ).

Let us take a particular e.By De?nition4.3,we have to prove thatρ|=χ,for allρ∈[[D. n i=1ask(c i)→A i]]′(e).

By equation E3of Table3and De?nitions4.1and4.3,[[D. n i=1ask(c i)→A i]]′(e)=D1∪D2, where

D1={ρ·ρ′|ρj(O)=ρj(I)andρj(I)?c i for each j∈[1,l(ρ)?1],i∈[1,n]

ρl(ρ)(I)?c h,ρl(ρ)(O)=ρl(ρ)(I)andρ′∈[[D.A h]]′(e)for an h∈[1,n]}and D2={ρ|ρj(O)=ρj(I)andρj(I)?c i for each j∈[1,l(ρ)],i∈[1,n]} Now,it is straightforward to prove that ifρ∈D2thenρ|=2( n j=1?I(c j)∧stut).Moreover, since by inductive hypothesis for each i∈[1,n],|=e D.A i satφi,we have that ifρ∈D1then ρ|= n i=1 ( n j=1?I(c j)∧stut)U(I(c i)∧stut∧ φi) and then the thesis.

Rule T3In this case?p now c then A else B sat(I(c)∧φ)∨(?I(c)∧ψ).Since the proofs

A satφand

B satψare shorter than the current one,the induction hypothesis says that for

every environment e,we have that|=e D.A satφand|=e D.B satψi.e.ρ|=φandρ′|=ψfor allρ∈[[D.A]]′(e)andρ′∈[[D.B]]′(e).

Let us take a particular e.By De?nition4.3,we have to prove thatρ|=(I(c)∧φ)∨(?I(c)∧ψ) for allρ∈[[D.now c then A else B]]′(e).Now the proof is immediate,by observing that by equation E4of Table3and De?nitions4.1and4.3,[[D.now c then A else B]]′(e)=D1∪D2, where

D1={ρ|ρ1(I)?c andρ∈[[D.A]]′(e)}and

D2={ρ′|ρ′1(I)?c andρ′∈[[D.B]]′(e)}.

Rule T4In this case?p?xA sat?x(φ∧loc(x))∧inv(x).Since the proof A satφis shorter than the current one,the induction hypothesis says that for every environment e,|=e D.A satφ

i.e.ρ′|=φfor allρ′∈[[D.A]]′(e).Let us consider a particular e.By De?nition4.3,we have

to prove thatρ|=?x(φ∧loc(x))∧inv(x),for allρ∈[[D.?xA]]′(e).By equation E6of Table3 and De?nitions4.1and4.3,ρ∈[[D.?xA]]′(e)if and only if there existsρ′∈[[D.A]]′(e)such that l(ρ)=l(ρ′)and the following conditions hold

1.for each i∈[1,l(ρ)],?xρi(I)=?xρ′i(I)and?xρi(O)=?xρ′i(O),

2.?xρ′1(I)=ρ′1(I)and for each i∈[2,l(ρ)],?xρ′i(I)?ρ′i?1(O)=ρ′i(I),

3.for each i∈[1,l(ρ)],ρi(O)=?xρi(O)?ρi(I).

Since for any sequenceρof predicate assignments and for any tccp process D.A,ρ∈[[D.A]]′(e) if and only if its‘projection’onto the distinguished predicates I and O generates a reactive sequence of D.A,by1.we can assume without loss of generality that?xρ=?xρ′.From2., the de?nition of loc(x)and the inductive hypothesis follows thatρ′|=φ∧loc(x).Therefore,by the previous equality and case1of Lemma4.4imply thatρ|=?x(φ∧loc(x))holds.Moreover by3.and by de?nition of inv(x)we obtain thatρ|=inv(x)thus proving the thesis for this case.

Rule T5In this case?p A B satχ,whereχis the formula

?X,Y(φ[X/O]∧ψ[Y/O]∧par(X,Y)),

X,Y∈M,X=Y and X,Y∈F V(φ)∪F V(ψ).Since the proofs A satφand B satψare shorter than the current one,the induction hypothesis says that for every environment e,we have that|=e D.A satφand|=e D.B satψi.e.ρ′|=φandρ′′|=ψfor allρ′∈[[D.A]]′(e)and ρ′′∈[[D.B]]′(e).

Let us take a particular e.By De?nition4.3,we have to prove thatρ|=χ,for allρ∈[[D.A

B]]′(e).Assume thatρ∈[[D.A B]]′(e).By equation E5of Table3and De?nitions4.1and

4.3,there existρ′∈[[D.A]]′(e)andρ′′∈[[D.B]]′(e)such that l(ρ)=l(ρ′)=l(ρ′′)and for

each i∈[1,l(ρ)],ρi(I)=ρ′i(I)=ρ′′i(I)andρi(O)=ρ′i(O)?ρ′i(O).Since for any sequence ρof predicate assignments and for any tccp process D.A,ρ∈[[D.A]]′(e)if and only if its ‘projection’on the distinguished predicates I and O generates a reactive sequence of D.A,by previous observation we can assume without loss of generality thatρi(Z)=ρ′i(Z)=ρ′′i(Z)for

each i∈[1,n]and for each Z∈M such that Z=O.Now we can construct a new sequence

ˉρof predicate assignments,of the same length ofρ,such thatˉρi(X)=ρ′i(O)ˉρi(Y)=ρ′′i(O)

ˉρi(Z)=ρi(Z)for each i∈[1,l(ρ)]and for each Z∈M such that Z=X,Y.Since X and Y

are not free inφandψand by inductive hypothesisρ′|=φandρ′′|=ψholds,by construction

we obtain thatˉρ|=φ[X/O]andˉρ|=ψ[Y/O].Moreover,by constructionˉρ|=par(X,Y)holds.

Thereforeˉρ|=φ[X/O]∧ψ[Y/O]∧par(X,Y)and the thesis follows from case1of Lemma4.4

by observing that?X,Yρ=?X,Yˉρ.

Rule T6In this case?p D.p(x)satφ.Since the proof D\{p}.p(x)satφ?p D\{p}.A satφis shorter than the current one,the induction hypothesis says that for every environment e such

that|=e D\{p}.p(x)satφwe also have that|=e D\{p}.A satφ.Let us take a particular e.

We have to show that|=e D.p(x)satφholds or,in other words,that ifρ∈[[D.p(x)]](e)then

we have thatρ|=φ.

Now[[D.p(x)]](e)=μΨ,whereμΨ= i f i,with f0=?and f i+1=[[D\{p}.A]](e{f i/p}).Thus

it su?ces to prove by induction that for all n,ifρ∈f n then,ρ|=φ.The base case is obvious.

Suppose that the thesis holds for f n,so for e′=e{f n/p}we have that|=e′D\{p}.p(x)satφ,

holds.Thus we infer that|=e′D\{p}.A satφ.Since by de?nition f n+1=[[D\{p}.A]](e{f n/p}),

we have that ifρ∈f n+1thenρ|=φwhich completes the proof.

Rule T7The proof is immediate.

Since R(A)=[[D.A]](e)holds for any closed process D.A with e arbitrary,whenever|=e D.A satφwe also have|=D.A satφ.Hence from the above result,with n=0,we can derive immediately the soundness of the system.

Corollary4.6(Soundness)The proof system consisting of the rules C0-C7is sound,that is,given a closed process D.A,if?p A satφthen|=D.A satφholds,for every correctness assertion D.A satφ.

Following the standard notion of completeness for Hoare-style proof systems as introduced by[13]we consider here a notion of relative completeness.We assume the existence of a property which describes exactly the denotation of a process,that is,we assume that for any process D.A there exists a formula, that for the sake of simplicity we denote byψ(A),such thatρ∈R′(A)i?ρ|=ψ(A)holds3.This is analogous to assume the expressibility of the strongest postcondition of a process P,as with standard Hoare-like proof systems.Furthermore,we assume as additional axioms all the valid temporal formulas, (for use in the consequence rule).Also this assumption,in general,is needed to obtain completeness of Hoare logics.

Analogously to the previous case,the completeness of the system is a corollary of the following Theorem.

Theorem4.7Let D={p1(x1)::A1,...,p n(x n)::A n}be a set of declarations and A an agent which involves only calls to procedures declared in D.Then we have

Φ1,...,Φn?p A satψ(A).

where,for i=1,...,n,Φi=p i(x i)satψ(p i(x i));.

Proof First observe that,for i=1,...,n,we can assume F V constr(ψ(p i(x i)))=?.In fact,from the de?nition of|=it follows thatρ∈R′(p i(x i))if and only ifρ|=γψ(p i(x i)),for each constraint assignment γ,and this holds if and only ifρ|=?constrψ(p i(x i)),where?constrψ(p i(x i))is the universal closure over

constraint variables of the formulaψ(p i(x i)).Therefore we can assume that all the constraint variables inψ(p i(x i))are universally quanti?ed,thus there are no free constraint variables.

We prove now,by induction on the complexity of A,thatΦ1,...,Φn?p A satψ(A)and F V constr(ψ(A))=?.

(tell(c))In this case,since F V constr(O(c)∧?p(O(p)→?q(I(q)∧q?c=p))∧ 2stut)=?,we have only to prove that

ψ(tell(c))=O(c)∧?p(O(p)→?q(I(q)∧q?c=p))∧ 2stut.

The proof is straightforward,since De?nition3.5,Theorem4.2and equation E2of Table3imply that the following equalities hold

R′(tell(c))={ρ|ρ1(O)=ρ1(I)?c andρi(O)=ρi(I)for i∈[2,l(ρ)]}.

(Σn i=1ask(c i)→A i)By inductive hypothesis we obtain that

Φ1,...,Φn?p A i satψ(A i)and F V constr(ψ(A i))=?,

for i=1,2,...,n.Then by rule T2we obtain also that

Φ1,...,Φn?p A satβ

where

β=

n

i=1

(n

j=1

?I j∧stut)U(I i∧stut∧ ψ(A i)) ∨2(n j=1?I j∧stut),

.

The inductive hypothesis implies that that

F V constr(β)=?.

Then,in order to prove the thesis we have to show that

β=ψ(Σn i=1ask(c i)→A i)

holds,that is,we have to prove thatρ∈R′(Σn i=1ask(c i)→A i)if and only ifρ|=β.

(Only if).Assume thatρ∈R′(Σn i=1ask(c i)→A i).By Theorem4.2,equation E4in Table3and De?nition4.1it follows thatρ∈D1∪D2where

D1={ρ·ρ′|ρj(O)=ρj(I)andρj(I)?c i for each j∈[1,l(ρ)?1],i∈[1,n]

ρl(ρ)(I)?c h,ρl(ρ)(O)=ρl(ρ)(I)andρ′∈[[D.A h]]′for an h∈[1,n]}and D2={ρ|ρj(O)=ρj(I)andρj(I)?c i for each j∈[1,l(ρ)],i∈[1,n]} By de?nition ofψ(A)and De?nition3.5,ifρ′∈[[D.A h]]′thenρ′|=ψ(A h).Therefore,ifρ∈D1then ρ|=( n j=1?I j∧stut)U(I i∧stut∧ ψ(A h))for an h∈[1,n]which impliesρ|=βby de?nition of disjunction and ofβ.

Ifρ∈D2then clearlyρ|=2( n j=1?I(c j)∧stut)and thereforeρ|=β.This complete the proof of the“Only if”part.The proof of the other implication is analogous(by using D1and D2above) and hence omitted.

(now c then A else B)By inductive hypothesis we obtain

Φ1,...,Φn?p A satψ(A),Φ1,...,Φn?p B satψ(B)and F V constr(ψ(A))=F V constr(ψ(B))=?.

Therefore rule T3implies that

Φ1,...,Φn?p now c then A else B sat(I(c)∧ψ(A))∨(?I(c)∧ψ(B)).

Since the inductive hypothesis implies also that F V constr((I(c)∧ψ(A))∨(?I(c)∧ψ(B)))=?,to prove the thesis we have only to show that

(I(c)∧ψ(A))∨(?I(c)∧ψ(B))=ψ(now c then A else B)

hold,that is,we have to show thatρ∈R′(now c then A else B)if and only ifρ|=(I(c)∧ψ(A))∨(?I(c)∧ψ(B)).The proof is straightforward,by observing that from the de?nition ofψ(A)and ψ(B),from De?nition3.5,Theorem4.2,equation E4of Table3and De?nition4.1it follows the following equality

R′(now c then A else B)={ρ|ρ1(I)?c andρ|=ψ(A)}∪

{ρ′|ρ′1(I)?c andρ′|=ψ(B)}.

(?x A)The inductive hypothesis implies that

Φ1,...,Φn?p A satψ(A)and F V constr(ψ(A))=?

and therefore,by rule T4,we obtain that

Φ1,...,Φn?p A sat?x(ψ(A)∧loc(x))∧inv(x).

From the inductive hypothesis and the de?nitions of loc(x)and of inv(x),we obtain that

F V constr(?x(ψ(A)∧loc(x))∧inv(x))=?.(1)

In order to prove the thesis,we have then to show that

?x(ψ(A)∧loc(x))∧inv(x)=ψ(?xA),

holds,that is,we have to prove thatρ∈R′(?xA)if and only ifρ|=?x(ψ(A)∧loc(x))∧inv(x).

Assume now thatρ∈R′(?xA).De?nition3.5,Theorem4.2,equation E6of Table3,De?nition4.1 and the de?nition ofψ(A)imply that there existsρ′such thatρ′|=ψ(A),l(ρ)=l(ρ′)and the following conditions hold:

1.for each i∈[1,l(ρ)],?xρi(I)=?xρ′i(I)and?xρi(O)=?xρ′i(O);

2.?xρ′1(I)=ρ′1(I)and for each i∈[2,l(ρ)],?xρ′i(I)?ρ′i?1(O)=ρ′i(I);

3.for each i∈[1,l(ρ)],ρi(O)=?xρi(O)?ρi(I).

Now the proof is analogous to that one already given for the case of Rule T4of Theorem4.5.

Conversely,assume thatρ|=?x(ψ(A)∧loc(x))∧inv(x).Then the following facts hold:

1.ρ|=inv(x).Therefore,by de?nition of inv(x),for each i∈[1,l(ρ)]the following holds

ρi(O)=?xρi(O)?ρi(I);(2)

2.ρ|=?x(ψ(A)∧loc(x)).Then,from case2of Lemma4.4and(1)we obtain thatρ′|=

ψ(A)∧loc(x)for someρ′such that

?xρ′=?xρ.(3) Sinceρ′|=ψ(A)∧loc(x),from the de?nition ofψ(A)and of loc(x)it follows that

ρ′∈R′(A)and(4)

?xρ′1(I)=ρ′1(I)and for each i∈[2,l(ρ)],?xρ′i(I)?ρ′i?1(O)=ρ′i(I).(5) From De?nition3.5,Theorem4.2,equation E6of Table3,De?nition4.1,(2),(3),4)and(5),it follows thatρ∈R′(?xA)and therefore the thesis holds.

(A1 A2)By inductive hypothesis we obtain that

Φ1,...,Φn?p A i satψ(A i)and F V constr(ψ(A i))=?,

for i=1,2.Then by rule T5we obtain also that

Φ1,...,Φn?p A sat?X,Y(ψ(A1)[X/O]∧ψ(A2)[Y/O]∧par(X,Y)),

where X,Y∈F V(ψ(A1))∪F V(ψ(A2))and X=Y.

The inductive hypothesis and the de?nition of par(X,Y)imply that

F V constr(?X,Y(ψ(A1)[X/O]∧ψ(A2)[Y/O]∧par(X,Y))=?.(6)

Then,in order to prove the thesis we have to show that

?X,Y(ψ(A1)[X/O]∧ψ(A2)[Y/O]∧par(X,Y))=ψ(A1 A2), holds,that is,we have to prove thatρ∈R′(A1 A2)if and only ifρ|=?X,Y(ψ(A1)[X/O]∧ψ(A2)[Y/O]∧par(X,Y)).

Assume thatρ∈R′(A1 A2).By De?nition3.5,Theorem4.2,equation E4in Table3and De?nition4.1it follows that there existρ′∈R′(A1)andρ′′∈R′(A2)such that l(ρ)=l(ρ′)=l(ρ′′) and,for each i∈[1,l(ρ)],ρi(I)=ρ′i(I)=ρ′′i(I)andρi(O)=ρ′i(O)?ρ′i(O)hold.Sinceρ′∈R′(A1), the de?nition ofψ(A1)implies thatρ′|=ψ(A1).Analogously we have thatρ′′|=ψ(A2).Now the proof is analogous to that one already shown for the case of Rule T5in the proof of Lemma4.5.

Conversely,assume thatρ|=?X,Y(ψ(A1)[X/O]∧ψ(A2)[Y/O]∧par(X,Y)).We have to prove that ρ∈R′(A1 A2).By case2of Lemma4.4and(6)there exists a sequence of predicate assignments ˉρsuch that?X,Yˉρ=?X,Yρandˉρ|=ψ(A1)[X/O]∧ψ(A2)[Y/O]∧par(X,Y).

We can now construct two new sequencesρ′andρ′′of predicate assignments having the same length asˉρ,such that,for each i∈[1,l(ˉρ)],

ρ′i(O)=ˉρi(X),ρ′′i(O)=ˉρi(Y)andρ′i(Z)=ρ′′i(Z)=ˉρi(Z),for each Z∈M,Z=O.(7) Since X,Y∈F V(ψ(A1))∪F V(ψ(A2))and X=Y,by construction it follows thatρ′|=ψ(A1)and ρ′′|=ψ(A2).Therefore,by de?nition ofψ(A),

ρ′∈R′(A1)andρ′′∈R′(A2).(8) Moreover,sinceˉρ|=par(X,Y),again by construction we obtain that,for i∈[1,l(ˉρ)],

ˉρi(O)=ρ′i(O)?ρ′′i(O)(9) holds.From De?nition3.5,Theorem4.2,equation E4in Table3,De?nition4.1,(7),(8)and(9) it follows thatˉρ∈R′(A1 A2).Observe now that,by de?nition,for any sequenceρof predicate assignments and for any tccp process A,ρ∈R′(A)if and only if its‘projection’on the distinguished predicates I and O generates a reactive sequence of R(A).Hence,since?X,Yˉρ=?X,Yρand ˉρ∈R′(A1 A2),we have thatρ∈R′(A1 A2)and therefore the thesis holds.

(A=p(y))Immediate.

From the above Theorem we derive the following corollary:

Corollary4.8(Completeness)Let D={p1(x1)::A1,...,p n(x n)::A n}and A n+1be an agent such that A i,for1≤i≤n+1,only involves calls to procedures declared in D.It follows that|=D.A n+1satφimplies?p D.A n+1satφ.

Proof By the above lemma we have for i=1,...,n that

Φ1,...,Φn?p A i satψ(D.p i(x i))

whereΦi=p i(x i)satψ(D.p i(x i))(note thatψ(D.A i)=ψ(D.p i(x i))).Now a repeated application of the recursion rule gives us?p D.p i(x i)satψ(D.p i(x i)).Again by the above lemma we have that

Φ1,...,Φn?p A n+1satψ(D.A n+1)

It follows by a straightforward induction on the length of the derivation(which does not involve applica-tions of the recursion rule)that

Φ′1,...,Φ′n?p D.A n+1satψ(D.A n+1)

whereΦ′i=D.p i(x i)satψ(D.p i(x i)),i=1,...,n.So,since?pΦ′i,i=1,...,n,we thus derive that ?p D.A n+1satψ(D.A n+1).Assume now that|=D.A n+1satφ.Then|=ψ(D.A n+1)→φholds and an application of C7gives us?p D.A n+1satφ.

The formulaψ(A)(analogous to the strongest postcondition)has been used to prove completeness. However,often to prove a property of a program it is su?cient to deal with some simpler property.The situation can be compared to the problem of?nding the suitable invariant when using the standard Hoare systems for imperative programming.

5Related and future work

We introduced a temporal logic for reasoning about the correctness of a timed extension of ccp and we proved the soundness and completeness of a related proof system.

A simpler temporal logic for tccp has been de?ned in[6]by considering epistemic operators of“belief”and“knowledge”which corresponds to the operators I and O considered in the present paper.Even though the intuitive ideas of the two papers are similar,the technical treatment is di?erent.In fact,the logic in[6]is less expressive than the present one,since it does not allow constraint(predicate)variables. As a consequence,the proof system de?ned in[6]was not complete.

Recently,a logic for a di?erent timed extension of ccp,called ntcc,has been presented in[24].The language ntcc[30,23]is a non deterministic extension of the timed ccp language de?ned in[27].Its com-putational model,and therefore the underlying logic,are rather di?erent from those that we considered. Analogously to the case of the ESTEREL language,computation in ntcc(and in the language de?ned in [27])proceeds in“bursts of activity”:in each phase a ccp process is executed to produce a response to an input provided by the environment.The process accumulates monotonically information in the store, according to the standard ccp computational model,until it reaches a“resting point”,i.e.a terminal state in which no more information can be generated.When the resting point is reached,the absence of events can be checked and it can trigger actions in the next time interval.Thus,each time interval is identi?ed with the time needed for a ccp process to terminate a computation.Clearly,in order to ensure that the next time instant is reached,the ccp process has to be always terminating,thus it is assumed that it does not contain recursion(a restricted form of recursion is allowed only across time boundaries). Furthermore,the programmer has to transfer explicitly the all information from a time instant to the next one by using special primitives,since at the end of a time interval all the constraints accumulated and all the processes suspended are discarded,unless they are argument to a speci?c primitive.These assumptions allow to obtain an elegant semantic model consisting of sequences of sets of resting points (each set describing the behavior at a time instant).

On the other hand,the tccp language that we consider has a di?erent notion of time,since each time-unit is identi?ed with the time needed for the underlying constraint system to accumulate the tell’s and to

answer the ask’s issued at each computation step by the processes of the system.This assumption allows us to obtain a direct timed extension of ccp which maintain the essential features of ccp computations. No restriction on recursion is needed to ensure that the next time instant is reached,since at each time instant there are only a?nite number of parallel agents which can perform a?nite number of(ask and tell)actions.Also,no explicit transfer of information across time boundaries is needed in tccp,since the (monotonic)evolution of the store is the same as in ccp(these di?erences a?ects the expressive power of the language,see[5]for a detailed discussion).Since the store grows monotonically,some syntactic restrictions are needed also in tccp in order to obtain bounded response time,that is,to be able to statically determine the maximal length of each time-unit(see[5]).

?From a logical point of view,as shown in[4]the set of resting points of a ccp process characterizes essen-tially the strongest post condition of the program(the characterization however is exact only for a certain class of programs).In[24]this logical view is integrated with(linear)temporal logic constructs which are interpreted in terms of sequences of sets of resting points,thus taking into account the temporal evolution of the system.A proof system for proving the resulting linear temporal properties is also de?ned in[24]. Since the resting points provide a compositional model(describing the?nal results of computations),in this approach there is no need for a semantic and logical representation of“assumptions”.On the other hand such a need arises when one wants to describe the input/output behavior of a process,which for generic(non deterministic)processes cannot be obtained from the resting points.Since tccp maintains essentially the ccp computational model,at each time instant rather than a set of?nal results(i.e.a set of resting points)we have an input/ouput behavior corresponding to the interaction of the environment, which provides the input,with the process,which produces the output.This is re?ected in the the logic we have de?ned.

Related to the present paper is also[14],where tcc speci?cations are represented in terms of graph structures in order to apply model checking techniques.A?nite interval of time(introduced by the user) is considered in order to obtain a?nite behavior of the tcc program,thus allowing the application of existing model checking algorithms.

Future work concerns the investigation of an axiomatization for the temporal logic introduced in this paper and the possibility of obtaining decision procedures,for example considering a semantic tableaux method.Since reactive sequences have been used also in the semantics of several other languages,including data?ow and imperative ones[21,10,9,12],we plan also to consider extensions of our logic to deal with these di?erent languages.

References

[1]L.Aceto and D.Murphy.Timing and causality in process algebra.Acta Informatica,33(4):317-350,

1996.

[2]J.Baeten and J.Bergstra.Real time process algebra.Formal Aspects of Computing,3(2):142-188,

1991.

[3]G.Berry and G.Gonthier.The ESTEREL programming language:Design,semantics and imple-

mentation.Science of Computer Programming,19(2):87-152,1992.

[4]F.S.de Boer,M.Gabbrielli,E.Marchiori and C.Palamidessi.Proving Concurrent Constraint

Programs Correct.Transactions on Programming Languages and Systems(TOPLAS),19(5):685-725.ACM Press,1997.

[5]F.S.de Boer,M.Gabbrielli and M.C.Meo.A Timed CCP https://www.doczj.com/doc/5815017866.html,rmation and Computation,

161,2000.

[6]F.S.de Boer,M.Gabbrielli and M.C.Meo.A Temporal Logic for reasoning about Timed Concurrent

Constraint Programs.In Proc.TIME01.IEEE Press,2001.

[7]F.S.de Boer,M.Gabbrielli,and M.C.Meo.Proving correctness of Timed Concurrent Constraint

Programs.In Proc FOSSACS02.LNCS2303,Springer-Verlag,2002.

[8]F.S.de Boer,J.N.Kok,C.Palamidessi,and J.J.M.M.Rutten.On Blocks:locality and asynchronous

communication.in Proc.of REX workshop on Semantics-Foundations and Applications,vol.666 of LNCS,pages73–90.Springer-Verlag,1992.

[9]F.S.de Boer,J.N.Kok,C.Palamidessi,and J.J.M.M.Rutten.The failure of failures in a paradigm

for asynchronous communication.In J.C.M.Baeten and J.F.Groote,editors,Proceedings of CON-CUR’91,vol.527of LNCS,pages111–126.Springer-Verlag,1991.

[10]F.S.de Boer and C.Palamidessi.A Fully Abstract Model for Concurrent Constraint Programming.

In S.Abramsky and T.S.E.Maibaum,editors,Proc.of TAPSOFT/CAAP,vol.493of LNCS,pages 296–319.Springer-Verlag,1991.

[11]P.Bremond-Gregoire and I.Lee.A Process Algebra of Communicating Shared Resources with Dense

Time and Priorities.Theoretical Computer Science189,1997.

Springer-Verlag,1997.

[12]S.Brookes.A fully abstract semantics of a shared variable parallel language.In Proc.Eighth IEEE

Symposium on Logic In Computer Science.IEEE Computer Society Press,1993.

[13]S.Cook,S.Soundness and completeness of an axiom system for program veri?cation.SIAM Journal

of Computation7,1,70–90.

[14]M.Falaschi,A.Policriti,A.Villanueva.Modeling Concurrent systems speci?ed in a Temporal Con-

current Constraint language.in Proc.AGP’2000.2000.

[15]M.Fisher.An introduction to Executable Temporal Logics.Knowledge Engineering Review,6(1):

43-56,1996.

[16]N.Halbwachs,P.Caspi,and D.Pilaud.The synchronous programming language LUSTRE.In Special

issue on Another Look at Real-time Systems,Proceedings of the IEEE,1991.

[17]D.Harel.Statecharts:A Visual Formalism for Complex Systems.Science of Computer Programming

8,pages231-274,1987.

[18]L.Henkin,J.D.Monk,and A.Tarski.Cylindric Algebras(Part I).North-Holland,1971.

[19]M.Hennessy and T.Regan.A temporal process https://www.doczj.com/doc/5815017866.html,rmation and Computation,117:221-

239,1995.

[20]P.Le Guernic,M.Le Borgue,T.Gauthier,and C.Le Marie.Programming real time applications

with SIGNAL.In Special issue on Another Look at Real-time Systems,Proceedings of the IEEE, 1991.

[21]B.Jonsson.A model and a proof system for asynchronous processes.In Proc.of the4th ACM Symp.

on Principles of Distributed Computing,pages49–58.ACM Press,1985.

[22]Z.Manna and A.Pnueli.The temporal logic of reactive systems.Springer-Verlag,1991.

[23]M.Nielsen and F.D.Valencia.The ntcc Calculus and its applications.Draft,2001.

[24]C.Palamidessi and F.D.Valencia.A Temporal Concurrent Constraint Programming Calculus.In

Proc.CP01,LNCS2239,pag.302-316.Springer-Verlag,2001.

[25]V.A.Saraswat.Concurrent Constraint Programming Languages.PhD thesis,Carnegie-Mellon Uni-

versity,January1989.Published by The MIT Press,1991.

[26]V.A.Saraswat and M.Rinard.Concurrent constraint programming.In Proc.of POPL,pages

232–245.ACM Press,1990.

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