Theorem fconstmpt 4651

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 3593	. . . 4 |- ( y e. { B } <-> y = B )
2	1	anbi2i 453	. . 3 |- ( ( x e. A /\ y e. { B } ) <-> ( x e. A /\ y = B ) )
3	2	opabbii 4049	. 2 |- { <. x , y >. | ( x e. A /\ y e. { B } ) } = { <. x , y >. | ( x e. A /\ y = B ) }
4		df-xp 4610	. 2 |- ( A X. { B } ) = { <. x , y >. | ( x e. A /\ y e. { B } ) }
5		df-mpt 4045	. 2 |- ( x e. A |-> B ) = { <. x , y >. | ( x e. A /\ y = B ) }
6	3, 4, 5	3eqtr4i 2196	1 |- ( A X. { B } ) = ( x e. A |-> B )

Syntax hints:   /\ wa 103   = wceq 1343   e. wcel 2136   {csn 3576   {copab 4042   |-> cmpt 4043   X. cxp 4602

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 699  ax-5 1435  ax-7 1436  ax-gen 1437  ax-ie1 1481  ax-ie2 1482  ax-8 1492  ax-10 1493  ax-11 1494  ax-i12 1495  ax-bndl 1497  ax-4 1498  ax-17 1514  ax-i9 1518  ax-ial 1522  ax-i5r 1523  ax-ext 2147

This theorem depends on definitions:  df-bi 116  df-tru 1346  df-nf 1449  df-sb 1751  df-clab 2152  df-cleq 2158  df-clel 2161  df-nfc 2297  df-v 2728  df-sn 3582  df-opab 4044  df-mpt 4045  df-xp 4610

This theorem is referenced by:  fconst  5383  fcoconst  5656  fmptsn  5674  fconstmpo  5937  ofc12  6070  caofinvl  6072  xpexgALT  6101  inftonninf  10376  fser0const  10451  prod1dc  11527  cnmptc  12922  dvexp  13315  dvexp2  13316  dvmptidcn  13318  dvmptccn  13319  dvef  13328  nninfall  13889  nninfsellemeqinf  13896  exmidsbthrlem  13901