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Metamath Proof Explorer

Theorem reldom

Description: Dominance is a relation. (Contributed by NM, 28-Mar-1998)

Ref Expression
Assertion reldom 
|- Rel ~<_

Proof

Step Hyp Ref Expression
1 df-dom 
 |-  ~<_ = { <. x , y >. | E. f f : x -1-1-> y }
2 1 relopabiv 
 |-  Rel ~<_