Theorem ce0lenc1 6240

Description: Cardinal exponentiation to zero is a cardinal iff the number is less than the size of cardinal one. (Contributed by SF, 18-Mar-2015.)

Assertion

Ref	Expression
ce0lenc1	⊢ (M ∈ NC → ((M ↑c 0c) ∈ NC ↔ M ≤c Nc 1c))

Proof of Theorem ce0lenc1

Dummy variables n x y are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		ce0tb 6239	. 2 ⊢ (M ∈ NC → ((M ↑c 0c) ∈ NC ↔ ∃n ∈ NC M = Tc n))
2		elncs 6120	. . . . . 6 ⊢ (n ∈ NC ↔ ∃x n = Nc x)
3		tceq 6159	. . . . . . . . 9 ⊢ (n = Nc x → Tc n = Tc Nc x)
4		vex 2863	. . . . . . . . . 10 ⊢ x ∈ V
5	4	tcnc 6226	. . . . . . . . 9 ⊢ Tc Nc x = Nc ℘1x
6	3, 5	syl6eq 2401	. . . . . . . 8 ⊢ (n = Nc x → Tc n = Nc ℘1x)
7		pw1ss1c 4159	. . . . . . . . 9 ⊢ ℘1x ⊆ 1c
8	4	pw1ex 4304	. . . . . . . . . 10 ⊢ ℘1x ∈ V
9		1cex 4143	. . . . . . . . . 10 ⊢ 1c ∈ V
10	8, 9	nclec 6196	. . . . . . . . 9 ⊢ (℘1x ⊆ 1c → Nc ℘1x ≤c Nc 1c)
11	7, 10	ax-mp 5	. . . . . . . 8 ⊢ Nc ℘1x ≤c Nc 1c
12	6, 11	syl6eqbr 4677	. . . . . . 7 ⊢ (n = Nc x → Tc n ≤c Nc 1c)
13	12	exlimiv 1634	. . . . . 6 ⊢ (∃x n = Nc x → Tc n ≤c Nc 1c)
14	2, 13	sylbi 187	. . . . 5 ⊢ (n ∈ NC → Tc n ≤c Nc 1c)
15		breq1 4643	. . . . 5 ⊢ (M = Tc n → (M ≤c Nc 1c ↔ Tc n ≤c Nc 1c))
16	14, 15	syl5ibrcom 213	. . . 4 ⊢ (n ∈ NC → (M = Tc n → M ≤c Nc 1c))
17	16	rexlimiv 2733	. . 3 ⊢ (∃n ∈ NC M = Tc n → M ≤c Nc 1c)
18	9	lenc 6224	. . . 4 ⊢ (M ∈ NC → (M ≤c Nc 1c ↔ ∃x ∈ M x ⊆ 1c))
19		ncseqnc 6129	. . . . . . 7 ⊢ (M ∈ NC → (M = Nc x ↔ x ∈ M))
20	19	biimpar 471	. . . . . 6 ⊢ ((M ∈ NC ∧ x ∈ M) → M = Nc x)
21	4	sspw12 4337	. . . . . . . 8 ⊢ (x ⊆ 1c ↔ ∃y x = ℘1y)
22		vex 2863	. . . . . . . . . . . 12 ⊢ y ∈ V
23	22	ncelncsi 6122	. . . . . . . . . . 11 ⊢ Nc y ∈ NC
24	22	tcnc 6226	. . . . . . . . . . 11 ⊢ Tc Nc y = Nc ℘1y
25		tceq 6159	. . . . . . . . . . . . 13 ⊢ (n = Nc y → Tc n = Tc Nc y)
26	25	eqeq1d 2361	. . . . . . . . . . . 12 ⊢ (n = Nc y → ( Tc n = Nc ℘1y ↔ Tc Nc y = Nc ℘1y))
27	26	rspcev 2956	. . . . . . . . . . 11 ⊢ (( Nc y ∈ NC ∧ Tc Nc y = Nc ℘1y) → ∃n ∈ NC Tc n = Nc ℘1y)
28	23, 24, 27	mp2an 653	. . . . . . . . . 10 ⊢ ∃n ∈ NC Tc n = Nc ℘1y
29		nceq 6109	. . . . . . . . . . . . 13 ⊢ (x = ℘1y → Nc x = Nc ℘1y)
30	29	eqeq1d 2361	. . . . . . . . . . . 12 ⊢ (x = ℘1y → ( Nc x = Tc n ↔ Nc ℘1y = Tc n))
31		eqcom 2355	. . . . . . . . . . . 12 ⊢ ( Nc ℘1y = Tc n ↔ Tc n = Nc ℘1y)
32	30, 31	syl6bb 252	. . . . . . . . . . 11 ⊢ (x = ℘1y → ( Nc x = Tc n ↔ Tc n = Nc ℘1y))
33	32	rexbidv 2636	. . . . . . . . . 10 ⊢ (x = ℘1y → (∃n ∈ NC Nc x = Tc n ↔ ∃n ∈ NC Tc n = Nc ℘1y))
34	28, 33	mpbiri 224	. . . . . . . . 9 ⊢ (x = ℘1y → ∃n ∈ NC Nc x = Tc n)
35	34	exlimiv 1634	. . . . . . . 8 ⊢ (∃y x = ℘1y → ∃n ∈ NC Nc x = Tc n)
36	21, 35	sylbi 187	. . . . . . 7 ⊢ (x ⊆ 1c → ∃n ∈ NC Nc x = Tc n)
37		eqeq1 2359	. . . . . . . 8 ⊢ (M = Nc x → (M = Tc n ↔ Nc x = Tc n))
38	37	rexbidv 2636	. . . . . . 7 ⊢ (M = Nc x → (∃n ∈ NC M = Tc n ↔ ∃n ∈ NC Nc x = Tc n))
39	36, 38	syl5ibr 212	. . . . . 6 ⊢ (M = Nc x → (x ⊆ 1c → ∃n ∈ NC M = Tc n))
40	20, 39	syl 15	. . . . 5 ⊢ ((M ∈ NC ∧ x ∈ M) → (x ⊆ 1c → ∃n ∈ NC M = Tc n))
41	40	rexlimdva 2739	. . . 4 ⊢ (M ∈ NC → (∃x ∈ M x ⊆ 1c → ∃n ∈ NC M = Tc n))
42	18, 41	sylbid 206	. . 3 ⊢ (M ∈ NC → (M ≤c Nc 1c → ∃n ∈ NC M = Tc n))
43	17, 42	impbid2 195	. 2 ⊢ (M ∈ NC → (∃n ∈ NC M = Tc n ↔ M ≤c Nc 1c))
44	1, 43	bitrd 244	1 ⊢ (M ∈ NC → ((M ↑c 0c) ∈ NC ↔ M ≤c Nc 1c))

Syntax hints:   → wi 4   ↔ wb 176   ∧ wa 358  ∃wex 1541   = wceq 1642   ∈ wcel 1710  ∃wrex 2616   ⊆ wss 3258  1_cc1c 4135  ℘₁cpw1 4136  0_cc0c 4375   class class class wbr 4640  (class class class)co 5526   NC cncs 6089   ≤_c clec 6090   Nc cnc 6092   T_c ctc 6094   ↑_c cce 6097

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-13 1712  ax-14 1714  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334  ax-nin 4079  ax-xp 4080  ax-cnv 4081  ax-1c 4082  ax-sset 4083  ax-si 4084  ax-ins2 4085  ax-ins3 4086  ax-typlower 4087  ax-sn 4088

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3or 935  df-3an 936  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-eu 2208  df-mo 2209  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2479  df-ne 2519  df-ral 2620  df-rex 2621  df-reu 2622  df-rmo 2623  df-rab 2624  df-v 2862  df-sbc 3048  df-nin 3212  df-compl 3213  df-in 3214  df-un 3215  df-dif 3216  df-symdif 3217  df-ss 3260  df-pss 3262  df-nul 3552  df-if 3664  df-pw 3725  df-sn 3742  df-pr 3743  df-uni 3893  df-int 3928  df-opk 4059  df-1c 4137  df-pw1 4138  df-uni1 4139  df-xpk 4186  df-cnvk 4187  df-ins2k 4188  df-ins3k 4189  df-imak 4190  df-cok 4191  df-p6 4192  df-sik 4193  df-ssetk 4194  df-imagek 4195  df-idk 4196  df-iota 4340  df-0c 4378  df-addc 4379  df-nnc 4380  df-fin 4381  df-lefin 4441  df-ltfin 4442  df-ncfin 4443  df-tfin 4444  df-evenfin 4445  df-oddfin 4446  df-sfin 4447  df-spfin 4448  df-phi 4566  df-op 4567  df-proj1 4568  df-proj2 4569  df-opab 4624  df-br 4641  df-1st 4724  df-swap 4725  df-sset 4726  df-co 4727  df-ima 4728  df-si 4729  df-id 4768  df-xp 4785  df-cnv 4786  df-rn 4787  df-dm 4788  df-res 4789  df-fun 4790  df-fn 4791  df-f 4792  df-f1 4793  df-fo 4794  df-f1o 4795  df-fv 4796  df-2nd 4798  df-ov 5527  df-oprab 5529  df-mpt 5653  df-mpt2 5655  df-txp 5737  df-compose 5749  df-ins2 5751  df-ins3 5753  df-image 5755  df-ins4 5757  df-si3 5759  df-funs 5761  df-fns 5763  df-pw1fn 5767  df-trans 5900  df-sym 5909  df-er 5910  df-ec 5948  df-qs 5952  df-map 6002  df-en 6030  df-ncs 6099  df-lec 6100  df-nc 6102  df-tc 6104  df-ce 6107

This theorem is referenced by:  nchoicelem8  6297  nchoicelem9  6298