Collections
Machines gathered the way a course or a question gathers them.
Beyond regular
Stacks, queues, counters and tapes: what each kind of memory buys.
Busy Beaver Hall of Fame
The champions: for each size, the halting machine that runs longest from a blank tape. Every step count here was checked by running the machine to its halt.
Three ways to never halt
One machine per non-halting proof the library can make: an exact cycle, a cycle that drifts along the tape, and a halt that can never be reached.
The ω-automata zoo
All eight acceptance conditions × determinism: Büchi, co-Büchi, parity and weak, deterministic and not — and the languages that tell them apart.
Regular languages, start to finish
DFAs, NFAs, ε-NFAs and two-way automata — the finite-memory machines, from the textbook classics to the showcase examples.
Machines that write
Moore and Mealy machines, finite-state and pushdown transducers, and a two-way transducer that copies its input.