Full Idea
And-Introduction (&I): Given A and B, we may derive A∧B as conclusion. This depends on their previous assumptions.
Clarification
∧ means 'and'
Gist of Idea
∧I: Given A and B, we may derive A∧B
Source
E.J. Lemmon (Beginning Logic [1965], 1.5)
Book Reference
Lemmon,E.J.: 'Beginning Logic' [Nelson 1979], p.40