What is Sequent?

In mathematical logic, a sequent is a very general kind of conditional assertion.

A sequent may have any number m of condition formulas Ai and any number n of asserted formulas Bj. A sequent is understood to mean that if all of the antecedent conditions are true, then at least one of the consequent formulas is true. This style of conditional assertion is almost always associated with the conceptual framework of sequent calculus.