Conjunction introduction (often abbreviated simply as conjunction and also called and introduction or adjunction)[1][2][3] is a valid rule of inference of propositional logic.

The rule makes it possible to introduce a conjunction into a logical proof.

is true, then the logical conjunction of the two propositions

The conjunction introduction rule may be written in sequent notation: where

are propositions expressed in some formal system, and

is a metalogical symbol meaning that

are each on lines of a proof in some logical system; This logic-related article is a stub.