ABSTRACT
I consider formulas from a propositional language w ith the connectives A, V and -> . A sequent shall be an ordered pair, consisting of a (possibly em pty) set M of formulas and a formula v ; sequents w ill be written as M = > v , and M is called the antecedent, v the succedent of the sequent. A sequent {m 0, ... m k_ J u M = $ v shall always be written as m0, ... , m k„1; M = > v . Observe that it is not requested that the sets M and {m 0, ... mk-1} be dis joint, nor that M be non-empty if k > 0 .
