Theorem receu 10263

Description: Existential uniqueness of reciprocals. Theorem I.8 of [Apostol] p. 18. (Contributed by NM, 29-Jan-1995.) (Revised by Mario Carneiro, 17-Feb-2014.)

Assertion

Ref	Expression
receu	|- ( ( A e. CC /\ B e. CC /\ B =/= 0 ) -> E! x e. CC ( B x. x ) = A )

Distinct variable groups:   x, A   x, B

Proof of Theorem receu

Dummy variable y is distinct from all other variables.

Step	Hyp	Ref	Expression
1		recex 10250	. . . 4 |- ( ( B e. CC /\ B =/= 0 ) -> E. y e. CC ( B x. y ) = 1 )
2	1	3adant1 1024	. . 3 |- ( ( A e. CC /\ B e. CC /\ B =/= 0 ) -> E. y e. CC ( B x. y ) = 1 )
3		simprl 763	. . . . . . 7 |- ( ( ( A e. CC /\ B e. CC ) /\ ( y e. CC /\ ( B x. y ) = 1 ) ) -> y e. CC )
4		simpll 759	. . . . . . 7 |- ( ( ( A e. CC /\ B e. CC ) /\ ( y e. CC /\ ( B x. y ) = 1 ) ) -> A e. CC )
5	3, 4	mulcld 9669	. . . . . 6 |- ( ( ( A e. CC /\ B e. CC ) /\ ( y e. CC /\ ( B x. y ) = 1 ) ) -> ( y x. A ) e. CC )
6		oveq1 6311	. . . . . . . 8 |- ( ( B x. y ) = 1 -> ( ( B x. y ) x. A ) = ( 1 x. A ) )
7	6	ad2antll 734	. . . . . . 7 |- ( ( ( A e. CC /\ B e. CC ) /\ ( y e. CC /\ ( B x. y ) = 1 ) ) -> ( ( B x. y ) x. A ) = ( 1 x. A ) )
8		simplr 761	. . . . . . . 8 |- ( ( ( A e. CC /\ B e. CC ) /\ ( y e. CC /\ ( B x. y ) = 1 ) ) -> B e. CC )
9	8, 3, 4	mulassd 9672	. . . . . . 7 |- ( ( ( A e. CC /\ B e. CC ) /\ ( y e. CC /\ ( B x. y ) = 1 ) ) -> ( ( B x. y ) x. A ) = ( B x. ( y x. A ) ) )
10	4	mulid2d 9667	. . . . . . 7 |- ( ( ( A e. CC /\ B e. CC ) /\ ( y e. CC /\ ( B x. y ) = 1 ) ) -> ( 1 x. A ) = A )
11	7, 9, 10	3eqtr3d 2472	. . . . . 6 |- ( ( ( A e. CC /\ B e. CC ) /\ ( y e. CC /\ ( B x. y ) = 1 ) ) -> ( B x. ( y x. A ) ) = A )
12		oveq2 6312	. . . . . . . 8 |- ( x = ( y x. A ) -> ( B x. x ) = ( B x. ( y x. A ) ) )
13	12	eqeq1d 2425	. . . . . . 7 |- ( x = ( y x. A ) -> ( ( B x. x ) = A <-> ( B x. ( y x. A ) ) = A ) )
14	13	rspcev 3183	. . . . . 6 |- ( ( ( y x. A ) e. CC /\ ( B x. ( y x. A ) ) = A ) -> E. x e. CC ( B x. x ) = A )
15	5, 11, 14	syl2anc 666	. . . . 5 |- ( ( ( A e. CC /\ B e. CC ) /\ ( y e. CC /\ ( B x. y ) = 1 ) ) -> E. x e. CC ( B x. x ) = A )
16	15	rexlimdvaa 2919	. . . 4 |- ( ( A e. CC /\ B e. CC ) -> ( E. y e. CC ( B x. y ) = 1 -> E. x e. CC ( B x. x ) = A ) )
17	16	3adant3 1026	. . 3 |- ( ( A e. CC /\ B e. CC /\ B =/= 0 ) -> ( E. y e. CC ( B x. y ) = 1 -> E. x e. CC ( B x. x ) = A ) )
18	2, 17	mpd 15	. 2 |- ( ( A e. CC /\ B e. CC /\ B =/= 0 ) -> E. x e. CC ( B x. x ) = A )
19		eqtr3 2451	. . . . . . 7 |- ( ( ( B x. x ) = A /\ ( B x. y ) = A ) -> ( B x. x ) = ( B x. y ) )
20		mulcan 10255	. . . . . . 7 |- ( ( x e. CC /\ y e. CC /\ ( B e. CC /\ B =/= 0 ) ) -> ( ( B x. x ) = ( B x. y ) <-> x = y ) )
21	19, 20	syl5ib 223	. . . . . 6 |- ( ( x e. CC /\ y e. CC /\ ( B e. CC /\ B =/= 0 ) ) -> ( ( ( B x. x ) = A /\ ( B x. y ) = A ) -> x = y ) )
22	21	3expa 1206	. . . . 5 |- ( ( ( x e. CC /\ y e. CC ) /\ ( B e. CC /\ B =/= 0 ) ) -> ( ( ( B x. x ) = A /\ ( B x. y ) = A ) -> x = y ) )
23	22	expcom 437	. . . 4 |- ( ( B e. CC /\ B =/= 0 ) -> ( ( x e. CC /\ y e. CC ) -> ( ( ( B x. x ) = A /\ ( B x. y ) = A ) -> x = y ) ) )
24	23	3adant1 1024	. . 3 |- ( ( A e. CC /\ B e. CC /\ B =/= 0 ) -> ( ( x e. CC /\ y e. CC ) -> ( ( ( B x. x ) = A /\ ( B x. y ) = A ) -> x = y ) ) )
25	24	ralrimivv 2846	. 2 |- ( ( A e. CC /\ B e. CC /\ B =/= 0 ) -> A. x e. CC A. y e. CC ( ( ( B x. x ) = A /\ ( B x. y ) = A ) -> x = y ) )
26		oveq2 6312	. . . 4 |- ( x = y -> ( B x. x ) = ( B x. y ) )
27	26	eqeq1d 2425	. . 3 |- ( x = y -> ( ( B x. x ) = A <-> ( B x. y ) = A ) )
28	27	reu4 3266	. 2 |- ( E! x e. CC ( B x. x ) = A <-> ( E. x e. CC ( B x. x ) = A /\ A. x e. CC A. y e. CC ( ( ( B x. x ) = A /\ ( B x. y ) = A ) -> x = y ) ) )
29	18, 25, 28	sylanbrc 669	1 |- ( ( A e. CC /\ B e. CC /\ B =/= 0 ) -> E! x e. CC ( B x. x ) = A )

Syntax hints:   -> wi 4   /\ wa 371   /\ w3a 983   = wceq 1438   e. wcel 1869   =/= wne 2619   A.wral 2776   E.wrex 2777   E!wreu 2778  (class class class)co 6304   CCcc 9543   0cc0 9545   1c1 9546   x. cmul 9550

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1666  ax-4 1679  ax-5 1749  ax-6 1795  ax-7 1840  ax-8 1871  ax-9 1873  ax-10 1888  ax-11 1893  ax-12 1906  ax-13 2054  ax-ext 2401  ax-sep 4545  ax-nul 4554  ax-pow 4601  ax-pr 4659  ax-un 6596  ax-resscn 9602  ax-1cn 9603  ax-icn 9604  ax-addcl 9605  ax-addrcl 9606  ax-mulcl 9607  ax-mulrcl 9608  ax-mulcom 9609  ax-addass 9610  ax-mulass 9611  ax-distr 9612  ax-i2m1 9613  ax-1ne0 9614  ax-1rid 9615  ax-rnegex 9616  ax-rrecex 9617  ax-cnre 9618  ax-pre-lttri 9619  ax-pre-lttrn 9620  ax-pre-ltadd 9621  ax-pre-mulgt0 9622

This theorem depends on definitions:  df-bi 189  df-or 372  df-an 373  df-3or 984  df-3an 985  df-tru 1441  df-ex 1661  df-nf 1665  df-sb 1788  df-eu 2270  df-mo 2271  df-clab 2409  df-cleq 2415  df-clel 2418  df-nfc 2573  df-ne 2621  df-nel 2622  df-ral 2781  df-rex 2782  df-reu 2783  df-rmo 2784  df-rab 2785  df-v 3084  df-sbc 3302  df-csb 3398  df-dif 3441  df-un 3443  df-in 3445  df-ss 3452  df-nul 3764  df-if 3912  df-pw 3983  df-sn 3999  df-pr 4001  df-op 4005  df-uni 4219  df-br 4423  df-opab 4482  df-mpt 4483  df-id 4767  df-po 4773  df-so 4774  df-xp 4858  df-rel 4859  df-cnv 4860  df-co 4861  df-dm 4862  df-rn 4863  df-res 4864  df-ima 4865  df-iota 5564  df-fun 5602  df-fn 5603  df-f 5604  df-f1 5605  df-fo 5606  df-f1o 5607  df-fv 5608  df-riota 6266  df-ov 6307  df-oprab 6308  df-mpt2 6309  df-er 7373  df-en 7580  df-dom 7581  df-sdom 7582  df-pnf 9683  df-mnf 9684  df-xr 9685  df-ltxr 9686  df-le 9687  df-sub 9868  df-neg 9869

This theorem is referenced by:  divmul  10279  divcl  10282  rexdiv  28400