end

isabelle extreme

Notice: no simp , no induct . Every proof step must explicitly invoke a primitive inference rule.

No – and that’s the point. isabelle-extreme is intentionally useless for application-scale verification. It lacks data types, recursion schemes, and any form of automation. Trying to prove 1+1=2 requires dozens of manual rewrite steps. However, as a and kernel sanity check , it is invaluable.

This opens a theory file with the extension .ext . Here’s a minimal example: