Deduction joining 3 implications to form implication of conjunctions.
(Contributed by NM, 24-Feb-2005.)
\( \vdash \varphi \rightarrow \psi \wedge \theta \wedge \eta \rightarrow \chi \wedge \tau \wedge \zeta \)
\( \vdash \varphi \rightarrow \psi \wedge \theta \wedge \eta \rightarrow \chi \wedge \tau \wedge \zeta \)
\( \vdash \psi \wedge \theta \wedge \eta \leftrightarrow \psi \wedge \theta \wedge \eta \)
\( \vdash \chi \wedge \tau \wedge \zeta \leftrightarrow \chi \wedge \tau \wedge \zeta \)