Theorem ssidd

Description: Weakening of ssid . (Contributed by BJ, 1-Sep-2022)

	Ref	Expression
Assertion	ssidd	$$⊢\phi \to A\subseteq A$$

Proof

Step	Hyp	Ref	Expression
1		ssid	$$⊢A\subseteq A$$
2	1	a1i	$$⊢\phi \to A\subseteq A$$