Category Archives: category theory

A subset interpretation (with context morphisms) of the sequent calculus for predicate logic

The previous two posts used the sequent calculus with a subset interpretation: We work with sequents , and interpret the propositions (and ) as subsets of some universe set . We interpret the sequent itself as . While writing the … Continue reading

Posted in category theory, logic, partial functions | Tagged , , | Leave a comment

Logic without truth

Pi is wrong! But so what? It is neither new, nor complicated enough to count as real math! And suggestions that  or  might be even better show that it not clear-cut either. I recently invested sufficient energy into some logical questions to … Continue reading

Posted in category theory, logic, partial functions | Tagged , , | 6 Comments

Learning category theory: a necessary evil?

The end of my last blog post (about isomorphism testing of reversible deterministic finite automata) explained how category theory gave me the idea that the simplified variant of my question about permutation group isomorphism should be easy to solve: The idea to consider … Continue reading

Posted in category theory, isomorphism | Tagged , | Leave a comment