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' '{' Predicate '}' ':' List Subjection

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

      | 'bounds' ':' List Subjection
      | 'bounds' '{' Predicate '}' ':' List Subjection

List ::= Expression | Expression ',' List

Predicate ::= Expression

Subjection ::=
	    // empty for no subjection
	  | under StrategyName
Predicate
an expression over a system state evaluating to either true or false. The predicate typically refers to a process location, but it can also use integers, logical operations and clock constraints.
Subjection
indicates whether the query should be subjected to a strategy.

For sup and bounds queries, the list of expressions may not contain clock constraints and must evaluate to either an integer or a clock.

See rail road diagram for the entire SymbolicQuery syntax.

See also: Semantics of the Symbolic Queries

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.
bounds{Train(1).Crossing}: Train(1).x
computes all individual intervals of Train(1).x when Train(1) is in Crossing. Introduced in UPPAAL 5.1.0-beta5.