Theorem halfnq 9798

Description: One-half of any positive fraction exists. Lemma for Proposition 9-2.6(i) of [Gleason] p. 120. (Contributed by NM, 16-Mar-1996.) (Revised by Mario Carneiro, 10-May-2013.) (New usage is discouraged.)

Assertion

Ref	Expression
halfnq	|- ( A e. Q. -> E. x ( x +Q x ) = A )

Distinct variable group:   x, A

Proof of Theorem halfnq

Step	Hyp	Ref	Expression
1		distrnq 9783	. . . 4 |- ( A .Q ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) = ( ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) +Q ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) )
2		distrnq 9783	. . . . . . . 8 |- ( ( 1Q +Q 1Q ) .Q ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) = ( ( ( 1Q +Q 1Q ) .Q ( *Q ` ( 1Q +Q 1Q ) ) ) +Q ( ( 1Q +Q 1Q ) .Q ( *Q ` ( 1Q +Q 1Q ) ) ) )
3		1nq 9750	. . . . . . . . . . 11 |- 1Q e. Q.
4		addclnq 9767	. . . . . . . . . . 11 |- ( ( 1Q e. Q. /\ 1Q e. Q. ) -> ( 1Q +Q 1Q ) e. Q. )
5	3, 3, 4	mp2an 708	. . . . . . . . . 10 |- ( 1Q +Q 1Q ) e. Q.
6		recidnq 9787	. . . . . . . . . 10 |- ( ( 1Q +Q 1Q ) e. Q. -> ( ( 1Q +Q 1Q ) .Q ( *Q ` ( 1Q +Q 1Q ) ) ) = 1Q )
7	5, 6	ax-mp 5	. . . . . . . . 9 |- ( ( 1Q +Q 1Q ) .Q ( *Q ` ( 1Q +Q 1Q ) ) ) = 1Q
8	7, 7	oveq12i 6662	. . . . . . . 8 |- ( ( ( 1Q +Q 1Q ) .Q ( *Q ` ( 1Q +Q 1Q ) ) ) +Q ( ( 1Q +Q 1Q ) .Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) = ( 1Q +Q 1Q )
9	2, 8	eqtri 2644	. . . . . . 7 |- ( ( 1Q +Q 1Q ) .Q ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) = ( 1Q +Q 1Q )
10	9	oveq1i 6660	. . . . . 6 |- ( ( ( 1Q +Q 1Q ) .Q ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) .Q ( *Q ` ( 1Q +Q 1Q ) ) ) = ( ( 1Q +Q 1Q ) .Q ( *Q ` ( 1Q +Q 1Q ) ) )
11	7	oveq2i 6661	. . . . . . 7 |- ( ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) .Q ( ( 1Q +Q 1Q ) .Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) = ( ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) .Q 1Q )
12		mulassnq 9781	. . . . . . . 8 |- ( ( ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) .Q ( 1Q +Q 1Q ) ) .Q ( *Q ` ( 1Q +Q 1Q ) ) ) = ( ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) .Q ( ( 1Q +Q 1Q ) .Q ( *Q ` ( 1Q +Q 1Q ) ) ) )
13		mulcomnq 9775	. . . . . . . . 9 |- ( ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) .Q ( 1Q +Q 1Q ) ) = ( ( 1Q +Q 1Q ) .Q ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) )
14	13	oveq1i 6660	. . . . . . . 8 |- ( ( ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) .Q ( 1Q +Q 1Q ) ) .Q ( *Q ` ( 1Q +Q 1Q ) ) ) = ( ( ( 1Q +Q 1Q ) .Q ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) .Q ( *Q ` ( 1Q +Q 1Q ) ) )
15	12, 14	eqtr3i 2646	. . . . . . 7 |- ( ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) .Q ( ( 1Q +Q 1Q ) .Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) = ( ( ( 1Q +Q 1Q ) .Q ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) .Q ( *Q ` ( 1Q +Q 1Q ) ) )
16		recclnq 9788	. . . . . . . . 9 |- ( ( 1Q +Q 1Q ) e. Q. -> ( *Q ` ( 1Q +Q 1Q ) ) e. Q. )
17		addclnq 9767	. . . . . . . . 9 |- ( ( ( *Q ` ( 1Q +Q 1Q ) ) e. Q. /\ ( *Q ` ( 1Q +Q 1Q ) ) e. Q. ) -> ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) e. Q. )
18	16, 16, 17	syl2anc 693	. . . . . . . 8 |- ( ( 1Q +Q 1Q ) e. Q. -> ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) e. Q. )
19		mulidnq 9785	. . . . . . . 8 |- ( ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) e. Q. -> ( ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) .Q 1Q ) = ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) )
20	5, 18, 19	mp2b 10	. . . . . . 7 |- ( ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) .Q 1Q ) = ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) )
21	11, 15, 20	3eqtr3i 2652	. . . . . 6 |- ( ( ( 1Q +Q 1Q ) .Q ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) .Q ( *Q ` ( 1Q +Q 1Q ) ) ) = ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) )
22	10, 21, 7	3eqtr3i 2652	. . . . 5 |- ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) = 1Q
23	22	oveq2i 6661	. . . 4 |- ( A .Q ( ( *Q ` ( 1Q +Q 1Q ) ) +Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) = ( A .Q 1Q )
24	1, 23	eqtr3i 2646	. . 3 |- ( ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) +Q ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) = ( A .Q 1Q )
25		mulidnq 9785	. . 3 |- ( A e. Q. -> ( A .Q 1Q ) = A )
26	24, 25	syl5eq 2668	. 2 |- ( A e. Q. -> ( ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) +Q ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) = A )
27		ovex 6678	. . 3 |- ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) e. _V
28		oveq12 6659	. . . . 5 |- ( ( x = ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) /\ x = ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) -> ( x +Q x ) = ( ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) +Q ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) )
29	28	anidms 677	. . . 4 |- ( x = ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) -> ( x +Q x ) = ( ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) +Q ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) )
30	29	eqeq1d 2624	. . 3 |- ( x = ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) -> ( ( x +Q x ) = A <-> ( ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) +Q ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) = A ) )
31	27, 30	spcev 3300	. 2 |- ( ( ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) +Q ( A .Q ( *Q ` ( 1Q +Q 1Q ) ) ) ) = A -> E. x ( x +Q x ) = A )
32	26, 31	syl 17	1 |- ( A e. Q. -> E. x ( x +Q x ) = A )

Syntax hints:   -> wi 4   = wceq 1483   E.wex 1704   e. wcel 1990   ` cfv 5888  (class class class)co 6650   Q.cnq 9674   1Qc1q 9675   +Q cplq 9677   .Q cmq 9678   *Qcrq 9679

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-8 1992  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-sep 4781  ax-nul 4789  ax-pow 4843  ax-pr 4906  ax-un 6949

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3or 1038  df-3an 1039  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-eu 2474  df-mo 2475  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ne 2795  df-ral 2917  df-rex 2918  df-reu 2919  df-rmo 2920  df-rab 2921  df-v 3202  df-sbc 3436  df-csb 3534  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-pss 3590  df-nul 3916  df-if 4087  df-pw 4160  df-sn 4178  df-pr 4180  df-tp 4182  df-op 4184  df-uni 4437  df-iun 4522  df-br 4654  df-opab 4713  df-mpt 4730  df-tr 4753  df-id 5024  df-eprel 5029  df-po 5035  df-so 5036  df-fr 5073  df-we 5075  df-xp 5120  df-rel 5121  df-cnv 5122  df-co 5123  df-dm 5124  df-rn 5125  df-res 5126  df-ima 5127  df-pred 5680  df-ord 5726  df-on 5727  df-lim 5728  df-suc 5729  df-iota 5851  df-fun 5890  df-fn 5891  df-f 5892  df-f1 5893  df-fo 5894  df-f1o 5895  df-fv 5896  df-ov 6653  df-oprab 6654  df-mpt2 6655  df-om 7066  df-1st 7168  df-2nd 7169  df-wrecs 7407  df-recs 7468  df-rdg 7506  df-1o 7560  df-oadd 7564  df-omul 7565  df-er 7742  df-ni 9694  df-pli 9695  df-mi 9696  df-lti 9697  df-plpq 9730  df-mpq 9731  df-enq 9733  df-nq 9734  df-erq 9735  df-plq 9736  df-mq 9737  df-1nq 9738  df-rq 9739

This theorem is referenced by:  nsmallnq  9799