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Metamath Proof Explorer

Theorem ssidd

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

Ref Expression
Assertion ssidd 
|- ( ph -> A C_ A )

Proof

Step Hyp Ref Expression
1 ssid 
 |-  A C_ A
2 1 a1i 
 |-  ( ph -> A C_ A )