# Realization Semantically

## Melvin Fitting

### Lehman College - CUNY Graduate Center

This talk continues my previous one from October 22. In that, I gave justification counterparts for S4.2 and for K4^3, possible world justification semantics, and a completeness proof. The completeness proof used a canonical model construction. Now I’l use that canonical model to prove, non-constructively, realization theorems for the two logics. The methodology is the same as in a paper of mine published in 2005, though the presentation has change somewhat. Primarily my motivation is to explore the range of modal logics having justification counterparts—to discover its extent and limits.

Lehman College Professor Melvin Fitting received the Herbrand Award of 2012 for his groundbreaking contributions to the field of automated theorem proving, which focuses on getting computer programs to prove logical and mathematical deductions.