MPE Home Metamath Proof Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  MPE Home  >  Th. List  >  df-doma Unicode version

Definition df-doma 13872
Description: Definition of the domain extractor for an arrow. (Contributed by FL, 24-Oct-2007.) (Revised by Mario Carneiro, 11-Jan-2017.)
Assertion
Ref Expression
df-doma  |- domA 
=  ( 1st  o.  1st )

Detailed syntax breakdown of Definition df-doma
StepHypRef Expression
1 cdoma 13868 . 2  class domA
2 c1st 6136 . . 3  class  1st
32, 2ccom 4709 . 2  class  ( 1st 
o.  1st )
41, 3wceq 1632 1  wff domA 
=  ( 1st  o.  1st )
Colors of variables: wff set class
This definition is referenced by:  homadm  13888  dmaf  13897
  Copyright terms: Public domain W3C validator