4 ms·
RE the OP's work to add probability-weighted state transitions, more generally TLA+ doesn't have the ability to talk about state transitions (i.e. actions in TL
by dwohnitmok 4y ago
RE the OP's work to add probability-weighted state transitions, more generally TLA+ doesn't have the ability to talk about state transitions (i.e. actions in TLA+) themselves in a first class way, which makes certain invariants very annoying or impossible to state (e.g. we will converge after no more than 5 steps). I wonder if there's a clean way to extend TLA+ to cover these cases. Admittedly they don't come up that frequently.
- nano_o 4y agoIn your example, you can just add a variable that is incremented at every step and then use it to state your invariant that convergence must happen within 5 steps. Sometimes you can encode properties that might initially seem hard to state in TLA+ in a similar way. Lamport has a recent paper explaining how to do that for hyperproperties such as information-flow security: http://lamport.azurewebsites.net/pubs/pubs.html?from=https://research.microsoft.com/users/lamport/pubs/pubs.html&type=path#hyper2 http://lamport.azurewebsites.net/pubs/pubs.html?from=https:/...