Theorem 3simpa

Simplification of triple conjunction. (Contributed by NM, 21-Apr-1994.) (Proof shortened by Wolf Lammen, 21-Jun-2022.)

Conclusion
\( \vdash \varphi \wedge \psi \wedge \chi \rightarrow \varphi \wedge \psi \)
Proof
id
3adant3 _