Theorem dfid2OLD

Description: Obsolete version of dfid2 as of 4-Nov-2024. (Contributed by NM, 15-Mar-2007) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Assertion	dfid2OLD	$$⊢\mathrm{I}=\left\{⟨x,x⟩|x=x\right\}$$

Proof

Step	Hyp	Ref	Expression
1		dfid3	$$⊢\mathrm{I}=\left\{⟨x,x⟩|x=x\right\}$$