Bisimulation serves as the identity criterion; in the finite case it is decidable via Paige–Tarjan partition refinement.
Computer science
The discipline entrances are dictionary-level correspondences: a ladder built in the other party's language, withdrawn once climbed.
The transition semigroup of the full 32-state rotor cell (coupled phase and magnitude) is solvable with group component ℤ₈; an S₈ counterexample marks the boundary.
Rotor Whole-Genome Analyzer: software for gene-regulatory-network fate prediction and knockout scans using the rotor (phase + magnitude) engine.