Conjunction elimination
Conjunction elimination is the inference that, if the conjunction A and B is true, then A is true, and B is true.
For instance, if it's true that it's raining, and I'm inside, then one may assert either term of the conjunction alone: it's raining, or I'm inside.
Formally:
or
( A ∧ B )
∴ A
( A ∧ B )
∴ B