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Metamath Proof Explorer

Theorem reli

Description: The identity relation is a relation. Part of Exercise 4.12(p) of Mendelson p. 235. (Contributed by NM, 26-Apr-1998) (Revised by Mario Carneiro, 21-Dec-2013)

Ref Expression
Assertion reli 
|- Rel _I

Proof

Step Hyp Ref Expression
1 df-id 
 |-  _I = { <. x , y >. | x = y }
2 1 relopabiv 
 |-  Rel _I