Theorem simpl

Description: Elimination of a conjunct. Theorem *3.26 (Simp) of WhiteheadRussell p. 112. (Contributed by NM, 3-Jan-1993) (Proof shortened by Wolf Lammen, 14-Jun-2022)

	Ref	Expression
Assertion	simpl	$$⊢\left(\phi \wedge \psi \right)\to \phi$$

Proof

Step	Hyp	Ref	Expression
1		id	$$⊢\phi \to \phi$$
2	1	adantr	$$⊢\left(\phi \wedge \psi \right)\to \phi$$