geolog-zeta-fork/examples/geolog/petri_reachability_vision.geolog

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2026-02-26 11:50:51 +01:00
// Petri Net Reachability Vision Test
// Based on 2025-12-12 design document
// Basic Petri net structure
theory PetriNet {
// Places
P : Sort;
// Transitions
T : Sort;
// Arcs (input to transitions, output from transitions)
in : Sort;
out : Sort;
in/src : in -> P;
in/tgt : in -> T;
out/src : out -> T;
out/tgt : out -> P;
}
// A marking is a multiset of tokens, each at a place
theory (N : PetriNet instance) Marking {
token : Sort;
token/of : token -> N/P;
}
// A reachability problem is: can we get from initial marking to target?
theory (N : PetriNet instance) ReachabilityProblem {
initial_marking : N Marking instance;
target_marking : N Marking instance;
}
// A trace is a sequence of firings connected by wires
theory (N : PetriNet instance) Trace {
// Firings of transitions
F : Sort;
F/of : F -> N/T;
// Wires connect firing outputs to firing inputs
W : Sort;
W/src : W -> [firing : F, arc : N/out];
W/tgt : W -> [firing : F, arc : N/in];
// Terminals are unconnected arc endpoints (to/from the initial/target markings)
input_terminal : Sort;
output_terminal : Sort;
input_terminal/of : input_terminal -> N/P;
output_terminal/of : output_terminal -> N/P;
input_terminal/tgt : input_terminal -> [firing : F, arc : N/in];
output_terminal/src : output_terminal -> [firing : F, arc : N/out];
}
// Example Petri net: A <--ab/ba--> B, (A,B) --abc--> C
instance ExampleNet : PetriNet = {
A : P;
B : P;
C : P;
ab : T;
ba : T;
abc : T;
ab_in : in;
ab_in in/src = A;
ab_in in/tgt = ab;
ab_out : out;
ab_out out/src = ab;
ab_out out/tgt = B;
ba_in : in;
ba_in in/src = B;
ba_in in/tgt = ba;
ba_out : out;
ba_out out/src = ba;
ba_out out/tgt = A;
abc_in1 : in;
abc_in1 in/src = A;
abc_in1 in/tgt = abc;
abc_in2 : in;
abc_in2 in/src = B;
abc_in2 in/tgt = abc;
abc_out : out;
abc_out out/src = abc;
abc_out out/tgt = C;
}
// Reachability problem: Can we reach B from A?
instance problem0 : ExampleNet ReachabilityProblem = {
initial_marking = {
t : token;
t token/of = ExampleNet/A;
};
target_marking = {
t : token;
t token/of = ExampleNet/B;
};
}