Dick de Jongh
ILLC, University of Amsterdam
Fatemeh Shirmohammadzadeh Maleki
Shahid Beheshti University
The weak subintuitionistic logic WF for which no standard unary modal companion is known is found to have a strict implication logic as a binary modal companion. It is also shown that for all modal logics extending the weak logic EN, classical modal logic with necessitation, a strict implication logic exists which is essentially equivalent to it. Among other things this means that any subintuitionistic logic which has a modal companion has a strict implication companion as well.