To help improve the shared understanding of how convergence locking (SyncPoints) should protect resources in progress. Why TLA+? It's used by many researchers and in industry (at AWS) to find bugs prior to implementation.
The easiest way to read the model is probably in PDF format. The ASCII version (obviously) can't represent familiar math symbols.
TLA+ is a language designed to closely mirror mathematics to make it easy to define systems in logical terms. More information on the language itself is available at the TLA+ project homepage
The easiest way is to download the toolbox environment and use that, but you can also just download the TLA+ checker if you want.
Apache 2.0, see LICENSE.txt for details.