Theorem bj-ssbid1

Description: A special case of sbequ1 . (Contributed by BJ, 22-Dec-2020)

	Ref	Expression
Assertion	bj-ssbid1	$$⊢\phi \to \left[x/x\right]\phi$$

Proof

Step	Hyp	Ref	Expression
1		equid	$$⊢x=x$$
2		sbequ1	$$⊢x=x\to \left(\phi \to \left[x/x\right]\phi \right)$$
3	1 2	ax-mp	$$⊢\phi \to \left[x/x\right]\phi$$