Theorem maxabslemval 10980

Description: Lemma for maxabs 10981. Value of the supremum. (Contributed by Jim Kingdon, 22-Dec-2021.)

Assertion

Ref	Expression
maxabslemval	|- ( ( A e. RR /\ B e. RR ) -> ( ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) e. RR /\ A. x e. { A , B } -. ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < x /\ A. x e. RR ( x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) -> E. z e. { A , B } x < z ) ) )

Distinct variable groups:   x, A, z   x, B, z

Proof of Theorem maxabslemval

Step	Hyp	Ref	Expression
1		readdcl 7746	. . . 4 |- ( ( A e. RR /\ B e. RR ) -> ( A + B ) e. RR )
2		simpl 108	. . . . . . 7 |- ( ( A e. RR /\ B e. RR ) -> A e. RR )
3	2	recnd 7794	. . . . . 6 |- ( ( A e. RR /\ B e. RR ) -> A e. CC )
4		simpr 109	. . . . . . 7 |- ( ( A e. RR /\ B e. RR ) -> B e. RR )
5	4	recnd 7794	. . . . . 6 |- ( ( A e. RR /\ B e. RR ) -> B e. CC )
6	3, 5	subcld 8073	. . . . 5 |- ( ( A e. RR /\ B e. RR ) -> ( A - B ) e. CC )
7	6	abscld 10953	. . . 4 |- ( ( A e. RR /\ B e. RR ) -> ( abs ` ( A - B ) ) e. RR )
8	1, 7	readdcld 7795	. . 3 |- ( ( A e. RR /\ B e. RR ) -> ( ( A + B ) + ( abs ` ( A - B ) ) ) e. RR )
9	8	rehalfcld 8966	. 2 |- ( ( A e. RR /\ B e. RR ) -> ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) e. RR )
10		vex 2689	. . . . 5 |- x e. _V
11	10	elpr 3548	. . . 4 |- ( x e. { A , B } <-> ( x = A \/ x = B ) )
12		maxabsle 10976	. . . . . . 7 |- ( ( A e. RR /\ B e. RR ) -> A <_ ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) )
13	2, 9, 12	lensymd 7884	. . . . . 6 |- ( ( A e. RR /\ B e. RR ) -> -. ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < A )
14		breq2 3933	. . . . . . 7 |- ( x = A -> ( ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < x <-> ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < A ) )
15	14	notbid 656	. . . . . 6 |- ( x = A -> ( -. ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < x <-> -. ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < A ) )
16	13, 15	syl5ibrcom 156	. . . . 5 |- ( ( A e. RR /\ B e. RR ) -> ( x = A -> -. ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < x ) )
17		maxabsle 10976	. . . . . . . . 9 |- ( ( B e. RR /\ A e. RR ) -> B <_ ( ( ( B + A ) + ( abs ` ( B - A ) ) ) / 2 ) )
18	17	ancoms 266	. . . . . . . 8 |- ( ( A e. RR /\ B e. RR ) -> B <_ ( ( ( B + A ) + ( abs ` ( B - A ) ) ) / 2 ) )
19	5, 3	addcomd 7913	. . . . . . . . . 10 |- ( ( A e. RR /\ B e. RR ) -> ( B + A ) = ( A + B ) )
20	5, 3	abssubd 10965	. . . . . . . . . 10 |- ( ( A e. RR /\ B e. RR ) -> ( abs ` ( B - A ) ) = ( abs ` ( A - B ) ) )
21	19, 20	oveq12d 5792	. . . . . . . . 9 |- ( ( A e. RR /\ B e. RR ) -> ( ( B + A ) + ( abs ` ( B - A ) ) ) = ( ( A + B ) + ( abs ` ( A - B ) ) ) )
22	21	oveq1d 5789	. . . . . . . 8 |- ( ( A e. RR /\ B e. RR ) -> ( ( ( B + A ) + ( abs ` ( B - A ) ) ) / 2 ) = ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) )
23	18, 22	breqtrd 3954	. . . . . . 7 |- ( ( A e. RR /\ B e. RR ) -> B <_ ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) )
24	4, 9, 23	lensymd 7884	. . . . . 6 |- ( ( A e. RR /\ B e. RR ) -> -. ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < B )
25		breq2 3933	. . . . . . 7 |- ( x = B -> ( ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < x <-> ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < B ) )
26	25	notbid 656	. . . . . 6 |- ( x = B -> ( -. ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < x <-> -. ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < B ) )
27	24, 26	syl5ibrcom 156	. . . . 5 |- ( ( A e. RR /\ B e. RR ) -> ( x = B -> -. ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < x ) )
28	16, 27	jaod 706	. . . 4 |- ( ( A e. RR /\ B e. RR ) -> ( ( x = A \/ x = B ) -> -. ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < x ) )
29	11, 28	syl5bi 151	. . 3 |- ( ( A e. RR /\ B e. RR ) -> ( x e. { A , B } -> -. ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < x ) )
30	29	ralrimiv 2504	. 2 |- ( ( A e. RR /\ B e. RR ) -> A. x e. { A , B } -. ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < x )
31		prid1g 3627	. . . . . . 7 |- ( A e. RR -> A e. { A , B } )
32	31	ad4antr 485	. . . . . 6 |- ( ( ( ( ( A e. RR /\ B e. RR ) /\ x e. RR ) /\ x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) ) /\ x < A ) -> A e. { A , B } )
33		breq2 3933	. . . . . . 7 |- ( z = A -> ( x < z <-> x < A ) )
34	33	rspcev 2789	. . . . . 6 |- ( ( A e. { A , B } /\ x < A ) -> E. z e. { A , B } x < z )
35	32, 34	sylancom 416	. . . . 5 |- ( ( ( ( ( A e. RR /\ B e. RR ) /\ x e. RR ) /\ x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) ) /\ x < A ) -> E. z e. { A , B } x < z )
36		prid2g 3628	. . . . . . 7 |- ( B e. RR -> B e. { A , B } )
37	36	ad4antlr 486	. . . . . 6 |- ( ( ( ( ( A e. RR /\ B e. RR ) /\ x e. RR ) /\ x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) ) /\ x < B ) -> B e. { A , B } )
38		breq2 3933	. . . . . . 7 |- ( z = B -> ( x < z <-> x < B ) )
39	38	rspcev 2789	. . . . . 6 |- ( ( B e. { A , B } /\ x < B ) -> E. z e. { A , B } x < z )
40	37, 39	sylancom 416	. . . . 5 |- ( ( ( ( ( A e. RR /\ B e. RR ) /\ x e. RR ) /\ x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) ) /\ x < B ) -> E. z e. { A , B } x < z )
41	2	ad2antrr 479	. . . . . 6 |- ( ( ( ( A e. RR /\ B e. RR ) /\ x e. RR ) /\ x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) ) -> A e. RR )
42	4	ad2antrr 479	. . . . . 6 |- ( ( ( ( A e. RR /\ B e. RR ) /\ x e. RR ) /\ x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) ) -> B e. RR )
43		simplr 519	. . . . . 6 |- ( ( ( ( A e. RR /\ B e. RR ) /\ x e. RR ) /\ x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) ) -> x e. RR )
44		simpr 109	. . . . . 6 |- ( ( ( ( A e. RR /\ B e. RR ) /\ x e. RR ) /\ x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) ) -> x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) )
45	41, 42, 43, 44	maxabslemlub 10979	. . . . 5 |- ( ( ( ( A e. RR /\ B e. RR ) /\ x e. RR ) /\ x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) ) -> ( x < A \/ x < B ) )
46	35, 40, 45	mpjaodan 787	. . . 4 |- ( ( ( ( A e. RR /\ B e. RR ) /\ x e. RR ) /\ x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) ) -> E. z e. { A , B } x < z )
47	46	ex 114	. . 3 |- ( ( ( A e. RR /\ B e. RR ) /\ x e. RR ) -> ( x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) -> E. z e. { A , B } x < z ) )
48	47	ralrimiva 2505	. 2 |- ( ( A e. RR /\ B e. RR ) -> A. x e. RR ( x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) -> E. z e. { A , B } x < z ) )
49	9, 30, 48	3jca 1161	1 |- ( ( A e. RR /\ B e. RR ) -> ( ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) e. RR /\ A. x e. { A , B } -. ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) < x /\ A. x e. RR ( x < ( ( ( A + B ) + ( abs ` ( A - B ) ) ) / 2 ) -> E. z e. { A , B } x < z ) ) )

Syntax hints:   -. wn 3   -> wi 4   /\ wa 103   \/ wo 697   /\ w3a 962   = wceq 1331   e. wcel 1480   A.wral 2416   E.wrex 2417   {cpr 3528   class class class wbr 3929   ` cfv 5123  (class class class)co 5774   RRcr 7619   + caddc 7623   < clt 7800   <_ cle 7801   - cmin 7933   / cdiv 8432   2c2 8771   abscabs 10769

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-in1 603  ax-in2 604  ax-io 698  ax-5 1423  ax-7 1424  ax-gen 1425  ax-ie1 1469  ax-ie2 1470  ax-8 1482  ax-10 1483  ax-11 1484  ax-i12 1485  ax-bndl 1486  ax-4 1487  ax-13 1491  ax-14 1492  ax-17 1506  ax-i9 1510  ax-ial 1514  ax-i5r 1515  ax-ext 2121  ax-coll 4043  ax-sep 4046  ax-nul 4054  ax-pow 4098  ax-pr 4131  ax-un 4355  ax-setind 4452  ax-iinf 4502  ax-cnex 7711  ax-resscn 7712  ax-1cn 7713  ax-1re 7714  ax-icn 7715  ax-addcl 7716  ax-addrcl 7717  ax-mulcl 7718  ax-mulrcl 7719  ax-addcom 7720  ax-mulcom 7721  ax-addass 7722  ax-mulass 7723  ax-distr 7724  ax-i2m1 7725  ax-0lt1 7726  ax-1rid 7727  ax-0id 7728  ax-rnegex 7729  ax-precex 7730  ax-cnre 7731  ax-pre-ltirr 7732  ax-pre-ltwlin 7733  ax-pre-lttrn 7734  ax-pre-apti 7735  ax-pre-ltadd 7736  ax-pre-mulgt0 7737  ax-pre-mulext 7738  ax-arch 7739  ax-caucvg 7740

This theorem depends on definitions:  df-bi 116  df-dc 820  df-3or 963  df-3an 964  df-tru 1334  df-fal 1337  df-nf 1437  df-sb 1736  df-eu 2002  df-mo 2003  df-clab 2126  df-cleq 2132  df-clel 2135  df-nfc 2270  df-ne 2309  df-nel 2404  df-ral 2421  df-rex 2422  df-reu 2423  df-rmo 2424  df-rab 2425  df-v 2688  df-sbc 2910  df-csb 3004  df-dif 3073  df-un 3075  df-in 3077  df-ss 3084  df-nul 3364  df-if 3475  df-pw 3512  df-sn 3533  df-pr 3534  df-op 3536  df-uni 3737  df-int 3772  df-iun 3815  df-br 3930  df-opab 3990  df-mpt 3991  df-tr 4027  df-id 4215  df-po 4218  df-iso 4219  df-iord 4288  df-on 4290  df-ilim 4291  df-suc 4293  df-iom 4505  df-xp 4545  df-rel 4546  df-cnv 4547  df-co 4548  df-dm 4549  df-rn 4550  df-res 4551  df-ima 4552  df-iota 5088  df-fun 5125  df-fn 5126  df-f 5127  df-f1 5128  df-fo 5129  df-f1o 5130  df-fv 5131  df-riota 5730  df-ov 5777  df-oprab 5778  df-mpo 5779  df-1st 6038  df-2nd 6039  df-recs 6202  df-frec 6288  df-pnf 7802  df-mnf 7803  df-xr 7804  df-ltxr 7805  df-le 7806  df-sub 7935  df-neg 7936  df-reap 8337  df-ap 8344  df-div 8433  df-inn 8721  df-2 8779  df-3 8780  df-4 8781  df-n0 8978  df-z 9055  df-uz 9327  df-rp 9442  df-seqfrec 10219  df-exp 10293  df-cj 10614  df-re 10615  df-im 10616  df-rsqrt 10770  df-abs 10771

This theorem is referenced by:  maxabs  10981  maxleast  10985