Theorem ondomcard 4868

Description: The class of ordinal numbers dominated by a set is a cardinal number. Theorem 59 of [Suppes] p. 228.

Assertion

Ref	Expression
ondomcard	|- (A e. B -> (card` {x e. On | x ~<_ A}) = {x e. On | x ~<_ A})

Distinct variable group:   x,A

Proof of Theorem ondomcard

Step	Hyp	Ref	Expression
1		elisset 1820	. 2 |- (A e. B -> A e. V)
2		ondomon 4867	. . . 4 |- (A e. V -> {x e. On | x ~<_ A} e. On)
3		domsdomtr 4482	. . . . . . . . . . . 12 |- ((y ~<_ A /\ A ~< {x e. On | x ~<_ A}) -> y ~< {x e. On | x ~<_ A})
4		breq1 2627	. . . . . . . . . . . . . 14 |- (x = y -> (x ~<_ A <-> y ~<_ A))
5	4	elrab 1908	. . . . . . . . . . . . 13 |- (y e. {x e. On | x ~<_ A} <-> (y e. On /\ y ~<_ A))
6	5	pm3.27bi 326	. . . . . . . . . . . 12 |- (y e. {x e. On | x ~<_ A} -> y ~<_ A)
7		eloni 2964	. . . . . . . . . . . . . . . 16 |- ({x e. On | x ~<_ A} e. On -> Ord {x e. On | x ~<_ A})
8		ordirr 2972	. . . . . . . . . . . . . . . 16 |- (Ord {x e. On | x ~<_ A} -> -. {x e. On | x ~<_ A} e. {x e. On | x ~<_ A})
9	7, 8	syl 10	. . . . . . . . . . . . . . 15 |- ({x e. On | x ~<_ A} e. On -> -. {x e. On | x ~<_ A} e. {x e. On | x ~<_ A})
10		hbrab1 1775	. . . . . . . . . . . . . . . . . 18 |- (y e. {x e. On | x ~<_ A} -> A.x y e. {x e. On | x ~<_ A})
11		ax-17 973	. . . . . . . . . . . . . . . . . 18 |- (y e. On -> A.x y e. On)
12		ax-17 973	. . . . . . . . . . . . . . . . . . 19 |- (y e. ~<_ -> A.x y e. ~<_ )
13		ax-17 973	. . . . . . . . . . . . . . . . . . 19 |- (y e. A -> A.x y e. A)
14	10, 12, 13	hbbr 2663	. . . . . . . . . . . . . . . . . 18 |- ({x e. On | x ~<_ A} ~<_ A -> A.x{x e. On | x ~<_ A} ~<_ A)
15		breq1 2627	. . . . . . . . . . . . . . . . . 18 |- (x = {x e. On | x ~<_ A} -> (x ~<_ A <-> {x e. On | x ~<_ A} ~<_ A))
16	10, 11, 14, 15	elrabf 1907	. . . . . . . . . . . . . . . . 17 |- ({x e. On | x ~<_ A} e. {x e. On | x ~<_ A} <-> ({x e. On | x ~<_ A} e. On /\ {x e. On | x ~<_ A} ~<_ A))
17	16	biimpr 152	. . . . . . . . . . . . . . . 16 |- (({x e. On | x ~<_ A} e. On /\ {x e. On | x ~<_ A} ~<_ A) -> {x e. On | x ~<_ A} e. {x e. On | x ~<_ A})
18	17	ex 373	. . . . . . . . . . . . . . 15 |- ({x e. On | x ~<_ A} e. On -> ({x e. On | x ~<_ A} ~<_ A -> {x e. On | x ~<_ A} e. {x e. On | x ~<_ A}))
19	9, 18	mtod 108	. . . . . . . . . . . . . 14 |- ({x e. On | x ~<_ A} e. On -> -. {x e. On | x ~<_ A} ~<_ A)
20	2, 19	syl 10	. . . . . . . . . . . . 13 |- (A e. V -> -. {x e. On | x ~<_ A} ~<_ A)
21		domtri 4848	. . . . . . . . . . . . . . 15 |- (({x e. On | x ~<_ A} e. On /\ A e. V) -> ({x e. On | x ~<_ A} ~<_ A <-> -. A ~< {x e. On | x ~<_ A}))
22	21	con2bid 528	. . . . . . . . . . . . . 14 |- (({x e. On | x ~<_ A} e. On /\ A e. V) -> (A ~< {x e. On | x ~<_ A} <-> -. {x e. On | x ~<_ A} ~<_ A))
23	2, 22	mpancom 707	. . . . . . . . . . . . 13 |- (A e. V -> (A ~< {x e. On | x ~<_ A} <-> -. {x e. On | x ~<_ A} ~<_ A))
24	20, 23	mpbird 196	. . . . . . . . . . . 12 |- (A e. V -> A ~< {x e. On | x ~<_ A})
25	3, 6, 24	syl2an 456	. . . . . . . . . . 11 |- ((y e. {x e. On | x ~<_ A} /\ A e. V) -> y ~< {x e. On | x ~<_ A})
26		sdomnen 4393	. . . . . . . . . . 11 |- (y ~< {x e. On | x ~<_ A} -> -. y ~~ {x e. On | x ~<_ A})
27	25, 26	syl 10	. . . . . . . . . 10 |- ((y e. {x e. On | x ~<_ A} /\ A e. V) -> -. y ~~ {x e. On | x ~<_ A})
28	27	expcom 374	. . . . . . . . 9 |- (A e. V -> (y e. {x e. On | x ~<_ A} -> -. y ~~ {x e. On | x ~<_ A}))
29	28	con2d 91	. . . . . . . 8 |- (A e. V -> (y ~~ {x e. On | x ~<_ A} -> -. y e. {x e. On | x ~<_ A}))
30		visset 1816	. . . . . . . . 9 |- y e. V
31	30	ensym 4418	. . . . . . . 8 |- ({x e. On | x ~<_ A} ~~ y -> y ~~ {x e. On | x ~<_ A})
32	29, 31	syl5 21	. . . . . . 7 |- (A e. V -> ({x e. On | x ~<_ A} ~~ y -> -. y e. {x e. On | x ~<_ A}))
33	32	adantr 391	. . . . . 6 |- ((A e. V /\ y e. On) -> ({x e. On | x ~<_ A} ~~ y -> -. y e. {x e. On | x ~<_ A}))
34		ontri1 2987	. . . . . . 7 |- (({x e. On | x ~<_ A} e. On /\ y e. On) -> ({x e. On | x ~<_ A} (_ y <-> -. y e. {x e. On | x ~<_ A}))
35	34, 2	sylan 450	. . . . . 6 |- ((A e. V /\ y e. On) -> ({x e. On | x ~<_ A} (_ y <-> -. y e. {x e. On | x ~<_ A}))
36	33, 35	sylibrd 204	. . . . 5 |- ((A e. V /\ y e. On) -> ({x e. On | x ~<_ A} ~~ y -> {x e. On | x ~<_ A} (_ y))
37	36	r19.21aiva 1717	. . . 4 |- (A e. V -> A.y e. On ({x e. On | x ~<_ A} ~~ y -> {x e. On | x ~<_ A} (_ y))
38	2, 37	jca 288	. . 3 |- (A e. V -> ({x e. On | x ~<_ A} e. On /\ A.y e. On ({x e. On | x ~<_ A} ~~ y -> {x e. On | x ~<_ A} (_ y)))
39		iscard2 4865	. . 3 |- ((card` {x e. On | x ~<_ A}) = {x e. On | x ~<_ A} <-> ({x e. On | x ~<_ A} e. On /\ A.y e. On ({x e. On | x ~<_ A} ~~ y -> {x e. On | x ~<_ A} (_ y)))
40	38, 39	sylibr 200	. 2 |- (A e. V -> (card` {x e. On | x ~<_ A}) = {x e. On | x ~<_ A})
41	1, 40	syl 10	1 |- (A e. B -> (card` {x e. On | x ~<_ A}) = {x e. On | x ~<_ A})

Syntax hints:  -. wn 2   -> wi 3   <-> wb 146   /\ wa 223   = wceq 958   e. wcel 960  A.wral 1648  {crab 1651  Vcvv 1814   (_ wss 2050   class class class wbr 2624  Ord word 2953  Oncon0 2954  ` cfv 3188   ~~ cen 4370   ~<_ cdom 4371   ~< csdm 4372  cardccrd 4823

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7  ax-7 964  ax-gen 965  ax-8 966  ax-9 967  ax-10 968  ax-11 969  ax-12 970  ax-13 971  ax-14 972  ax-17 973  ax-4 975  ax-5o 977  ax-6o 980  ax-9o 1125  ax-10o 1142  ax-16 1212  ax-11o 1220  ax-ext 1462  ax-rep 2698  ax-sep 2708  ax-nul 2715  ax-pow 2748  ax-pr 2785  ax-un 2872  ax-ac 4754

This theorem depends on definitions:  df-bi 147  df-or 224  df-an 225  df-3or 778  df-3an 779  df-ex 983  df-sb 1174  df-eu 1384  df-mo 1385  df-clab 1467  df-cleq 1472  df-clel 1475  df-ne 1590  df-ral 1652  df-rex 1653  df-reu 1654  df-rab 1655  df-v 1815  df-sbc 1945  df-dif 2052  df-un 2053  df-in 2054  df-ss 2056  df-nul 2284  df-pw 2406  df-sn 2416  df-pr 2417  df-tp 2419  df-op 2420  df-uni 2508  df-int 2538  df-iun 2572  df-br 2625  df-opab 2672  df-tr 2686  df-eprel 2838  df-id 2841  df-po 2846  df-so 2856  df-fr 2923  df-we 2940  df-ord 2957  df-on 2958  df-suc 2960  df-xp 3190  df-rel 3191  df-cnv 3192  df-co 3193  df-dm 3194  df-rn 3195  df-res 3196  df-ima 3197  df-fun 3198  df-fn 3199  df-f 3200  df-f1 3201  df-fo 3202  df-f1o 3203  df-fv 3204  df-er 4267  df-en 4374  df-dom 4375  df-sdom 4376  df-card 4826

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