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Syntax of Symbolic Queries

Symbolic Queries

Symbolic queries are performed using symbolic operations based on symbolic semantics of timed automata and correspond to a mathematically rigorous proof.

SymbolicQuery ::=
        'A[]' Expression Subjection
      | 'E<>' Expression Subjection
      | 'E[]' Expression Subjection
      | 'A<>' Expression Subjection
      | Expression --> Expression Subjection

      | 'sup' ':' List Subjection
      | 'sup' '{' Expression '}' ':' List Subjection

      | 'inf' ':' List Subjection
      | 'inf' '{' Expression '}' ':' List Subjection

List ::= Expression | Expression ',' List

Subjection ::=
	    // empty for no subjection
	  | under StrategyName

Subjection: indicates whether the query should be subjected to a strategy.

For sup properties, expression may not contain clock constraints and must evaluate to either an integer or a clock.

See rail road diagram for the entire SymbolicQuery syntax.

Examples

A[] 1<2: invariantly 1<2.
E<> p1.cs and p2.cs: true if the system can reach a state where both process p1 and p2 are in their locations cs.
A[] p1.cs imply not p2.cs: invariantly process p1 in location cs implies that process p2 is not in location cs.
A[] not deadlock: invariantly the process is not deadlocked.
sup: Train(1).x, Train(2).x: computes the suprema of Train(1).x and Train(2).x expressions (maximal values in case of integers, upper bounds, strict or not, for clocks).
sup{Train(1).Crossing}: Train(1).x: computes the supremum of Train(1).x but only when Train(1) is in Crossing.
inf{Gate.Occ}: Gate.len: similarly to sup, infquery computes infimum of the given expression Gate.len while process Gate is in Occ location. When a clock infimum is needed, the state predicate should be used, otherwise the result is trivially >=0.