What is TLA+?
TLA+ is a modeling language in which one can model technical systems with discrete states. It has been used to describe many things, from the jugs problem in Die Hard 3 over a diverse array of algorithms up to Amazon Storage Services. The power of TLA+ comes from the TLC Model Checker, which checks your model for certain properties. These properties could be invariants — statements that are true of every possible state, like there are no buffer overruns. And it can check temporal properties — e.g., that an algorithm eventually finishes.