Theorem fald

Description: Refutation of falsity, in deduction form. (Contributed by Giovanni Mascellani, 24-Mar-2018)

	Ref	Expression
Assertion	fald	|- ( th -> -. F. )

Proof

Step	Hyp	Ref	Expression
1		fal	|- -. F.
2	1	a1i	|- ( th -> -. F. )