FUNKTORY ASERCJI I KONIUNKCJI SEKWENCYJNEJ

An axiomatic characterisation of the functor of sequential assertion is propsed here. By means of it the functor of sequential conjunction is defined. In the temporal interpretation these functors are respectively read as: next/then and and-next/and-then. It is proved that the proposed system (SAS) and its strenghtening (SAS*) comprise respectively von Wright’s And Next and And Then systems. The consistency and independence of axioms of the richer of the two proposed structures (SAS*) is settled by interpretation in the quadrivalent propositional calculus.