In tense logic with operators (‘it has always been the case that…’) and (‘it will be the case that…’), the axiom scheme:
Hamblin’s axiom corresponds to the discreteness of time, that is, for any moment , there exists a future moment such that only and its predecessors come before . Hamblin’s axiom is named for philosopher C. L. Hamblin (1922–1985), whose work influenced the early development of tense logic.