The minimal system ${\rm L}'_0$.
Xue Gang Wang · Notre Dame Journal of Formal Logic · 1992
In this paper, I consider a tense logic of the class of arbitrary orders which has H,G,H',G' as its tense operators and has the usual formal semantics.For the tense logic, a sound and complete axiomatic system L' o is established, using the method of deductively closed sets and maximal consistent sets.