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The Herodotus release

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@lemmy lemmy released this 08 Jan 14:50
· 2243 commits to master since this release

This release does not completely address the important bug discussed below

Important bugfix

This release fixes a rare but serious bug that has been in TLC since its initial implementation. TLC could generate an incorrect set of initial states, and hence not examine all reachable states, in the following situation:

The possible initial values of some variable var are specified by a subformula: F(..., var , ...) in the initial predicate, for some operator F such that expanding the definition of F results in a formula containing more than one occurrence of var, not all occurring in separate disjuncts of that formula. An example is an initial predicate Init defined as follows:


F(var) == \/ var \in 0..99 /\ var % 2 = 0
          \/ var = -1

Init == /\ F(x)
        /\ ...

The error would not appear if F were defined by

F(var) == \/ var \in {i \in 0..99 : i % 2 = 0}
          \/ var = -1

or if the definition of F(x) were expanded in Init:

Init == /\ \/ var \in 0..99 /\ var % 2 = 0
           \/ var = -1
        /\ ...

Additional noteworthy changes


The high level changelog is available at The 1.5.5 milestone lists all completed issues. Github has a more technical changelog listing all commits..

32 bits

32 bit (x86) variants of the TLA Toolbox can be downloaded from our alternative download site.


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