Theorem eel021old

Description: el021old without virtual deductions. (Contributed by Alan Sare, 13-Jun-2015) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypotheses	eel021.1	$$⊢\phi$$
	eel021.2	$$⊢\left(\psi \wedge \chi \right)\to \theta$$
	eel021.3	$$⊢\left(\phi \wedge \theta \right)\to \tau$$
Assertion	eel021old	$$⊢\left(\psi \wedge \chi \right)\to \tau$$

Proof

Step	Hyp	Ref	Expression
1		eel021.1	$$⊢\phi$$
2		eel021.2	$$⊢\left(\psi \wedge \chi \right)\to \theta$$
3		eel021.3	$$⊢\left(\phi \wedge \theta \right)\to \tau$$
4	1 2 3	sylancr	$$⊢\left(\psi \wedge \chi \right)\to \tau$$