Theorem fconstmpt 4658

Description: Representation of a constant function using the mapping operation. (Note that x cannot appear free in B.) (Contributed by NM, 12-Oct-1999.) (Revised by Mario Carneiro, 16-Nov-2013.)

Assertion

Ref	Expression
fconstmpt	|- ( A X. { B } ) = ( x e. A |-> B )

Distinct variable groups:   x, A   x, B

Proof of Theorem fconstmpt

Dummy variable y is distinct from all other variables.

Step	Hyp	Ref	Expression
1		velsn 3600	. . . 4 |- ( y e. { B } <-> y = B )
2	1	anbi2i 454	. . 3 |- ( ( x e. A /\ y e. { B } ) <-> ( x e. A /\ y = B ) )
3	2	opabbii 4056	. 2 |- { <. x , y >. | ( x e. A /\ y e. { B } ) } = { <. x , y >. | ( x e. A /\ y = B ) }
4		df-xp 4617	. 2 |- ( A X. { B } ) = { <. x , y >. | ( x e. A /\ y e. { B } ) }
5		df-mpt 4052	. 2 |- ( x e. A |-> B ) = { <. x , y >. | ( x e. A /\ y = B ) }
6	3, 4, 5	3eqtr4i 2201	1 |- ( A X. { B } ) = ( x e. A |-> B )

Syntax hints:   /\ wa 103   = wceq 1348   e. wcel 2141   {csn 3583   {copab 4049   |-> cmpt 4050   X. cxp 4609

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 704  ax-5 1440  ax-7 1441  ax-gen 1442  ax-ie1 1486  ax-ie2 1487  ax-8 1497  ax-10 1498  ax-11 1499  ax-i12 1500  ax-bndl 1502  ax-4 1503  ax-17 1519  ax-i9 1523  ax-ial 1527  ax-i5r 1528  ax-ext 2152

This theorem depends on definitions:  df-bi 116  df-tru 1351  df-nf 1454  df-sb 1756  df-clab 2157  df-cleq 2163  df-clel 2166  df-nfc 2301  df-v 2732  df-sn 3589  df-opab 4051  df-mpt 4052  df-xp 4617

This theorem is referenced by:  fconst  5393  fcoconst  5667  fmptsn  5685  fconstmpo  5948  ofc12  6081  caofinvl  6083  xpexgALT  6112  inftonninf  10397  fser0const  10472  prod1dc  11549  cnmptc  13076  dvexp  13469  dvexp2  13470  dvmptidcn  13472  dvmptccn  13473  dvef  13482  nninfall  14042  nninfsellemeqinf  14049  exmidsbthrlem  14054