Theorem knatar 6507

Description: The Knaster-Tarski theorem says that every monotone function over a complete lattice has a (least) fixpoint. Here we specialize this theorem to the case when the lattice is the powerset lattice 𝒫 𝐴. (Contributed by Mario Carneiro, 11-Jun-2015.)

Hypothesis

Ref	Expression
knatar.1	⊢ 𝑋 = ∩ {𝑧 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑧) ⊆ 𝑧}

Assertion

Ref	Expression
knatar	⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → (𝑋 ⊆ 𝐴 ∧ (𝐹‘𝑋) = 𝑋))

Distinct variable groups:   𝑥,𝑦,𝑧,𝐴   𝑥,𝐹,𝑦,𝑧   𝑥,𝑋,𝑦

Allowed substitution hints:   𝑉(𝑥,𝑦,𝑧)   𝑋(𝑧)

Proof of Theorem knatar

Dummy variable 𝑤 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		knatar.1	. . 3 ⊢ 𝑋 = ∩ {𝑧 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑧) ⊆ 𝑧}
2		pwidg 4121	. . . . 5 ⊢ (𝐴 ∈ 𝑉 → 𝐴 ∈ 𝒫 𝐴)
3	2	3ad2ant1 1075	. . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → 𝐴 ∈ 𝒫 𝐴)
4		simp2 1055	. . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → (𝐹‘𝐴) ⊆ 𝐴)
5		fveq2 6103	. . . . . 6 ⊢ (𝑧 = 𝐴 → (𝐹‘𝑧) = (𝐹‘𝐴))
6		id 22	. . . . . 6 ⊢ (𝑧 = 𝐴 → 𝑧 = 𝐴)
7	5, 6	sseq12d 3597	. . . . 5 ⊢ (𝑧 = 𝐴 → ((𝐹‘𝑧) ⊆ 𝑧 ↔ (𝐹‘𝐴) ⊆ 𝐴))
8	7	intminss 4438	. . . 4 ⊢ ((𝐴 ∈ 𝒫 𝐴 ∧ (𝐹‘𝐴) ⊆ 𝐴) → ∩ {𝑧 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑧) ⊆ 𝑧} ⊆ 𝐴)
9	3, 4, 8	syl2anc 691	. . 3 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → ∩ {𝑧 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑧) ⊆ 𝑧} ⊆ 𝐴)
10	1, 9	syl5eqss 3612	. 2 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → 𝑋 ⊆ 𝐴)
11		fveq2 6103	. . . . . . . . . . . . . 14 ⊢ (𝑧 = 𝑤 → (𝐹‘𝑧) = (𝐹‘𝑤))
12		id 22	. . . . . . . . . . . . . 14 ⊢ (𝑧 = 𝑤 → 𝑧 = 𝑤)
13	11, 12	sseq12d 3597	. . . . . . . . . . . . 13 ⊢ (𝑧 = 𝑤 → ((𝐹‘𝑧) ⊆ 𝑧 ↔ (𝐹‘𝑤) ⊆ 𝑤))
14	13	intminss 4438	. . . . . . . . . . . 12 ⊢ ((𝑤 ∈ 𝒫 𝐴 ∧ (𝐹‘𝑤) ⊆ 𝑤) → ∩ {𝑧 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑧) ⊆ 𝑧} ⊆ 𝑤)
15	14	adantl 481	. . . . . . . . . . 11 ⊢ (((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) ∧ (𝑤 ∈ 𝒫 𝐴 ∧ (𝐹‘𝑤) ⊆ 𝑤)) → ∩ {𝑧 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑧) ⊆ 𝑧} ⊆ 𝑤)
16	1, 15	syl5eqss 3612	. . . . . . . . . 10 ⊢ (((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) ∧ (𝑤 ∈ 𝒫 𝐴 ∧ (𝐹‘𝑤) ⊆ 𝑤)) → 𝑋 ⊆ 𝑤)
17		vex 3176	. . . . . . . . . . 11 ⊢ 𝑤 ∈ V
18	17	elpw2 4755	. . . . . . . . . 10 ⊢ (𝑋 ∈ 𝒫 𝑤 ↔ 𝑋 ⊆ 𝑤)
19	16, 18	sylibr 223	. . . . . . . . 9 ⊢ (((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) ∧ (𝑤 ∈ 𝒫 𝐴 ∧ (𝐹‘𝑤) ⊆ 𝑤)) → 𝑋 ∈ 𝒫 𝑤)
20		simprl 790	. . . . . . . . . 10 ⊢ (((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) ∧ (𝑤 ∈ 𝒫 𝐴 ∧ (𝐹‘𝑤) ⊆ 𝑤)) → 𝑤 ∈ 𝒫 𝐴)
21		simpl3 1059	. . . . . . . . . 10 ⊢ (((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) ∧ (𝑤 ∈ 𝒫 𝐴 ∧ (𝐹‘𝑤) ⊆ 𝑤)) → ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥))
22		pweq 4111	. . . . . . . . . . . 12 ⊢ (𝑥 = 𝑤 → 𝒫 𝑥 = 𝒫 𝑤)
23		fveq2 6103	. . . . . . . . . . . . 13 ⊢ (𝑥 = 𝑤 → (𝐹‘𝑥) = (𝐹‘𝑤))
24	23	sseq2d 3596	. . . . . . . . . . . 12 ⊢ (𝑥 = 𝑤 → ((𝐹‘𝑦) ⊆ (𝐹‘𝑥) ↔ (𝐹‘𝑦) ⊆ (𝐹‘𝑤)))
25	22, 24	raleqbidv 3129	. . . . . . . . . . 11 ⊢ (𝑥 = 𝑤 → (∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥) ↔ ∀𝑦 ∈ 𝒫 𝑤(𝐹‘𝑦) ⊆ (𝐹‘𝑤)))
26	25	rspcv 3278	. . . . . . . . . 10 ⊢ (𝑤 ∈ 𝒫 𝐴 → (∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥) → ∀𝑦 ∈ 𝒫 𝑤(𝐹‘𝑦) ⊆ (𝐹‘𝑤)))
27	20, 21, 26	sylc 63	. . . . . . . . 9 ⊢ (((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) ∧ (𝑤 ∈ 𝒫 𝐴 ∧ (𝐹‘𝑤) ⊆ 𝑤)) → ∀𝑦 ∈ 𝒫 𝑤(𝐹‘𝑦) ⊆ (𝐹‘𝑤))
28		fveq2 6103	. . . . . . . . . . 11 ⊢ (𝑦 = 𝑋 → (𝐹‘𝑦) = (𝐹‘𝑋))
29	28	sseq1d 3595	. . . . . . . . . 10 ⊢ (𝑦 = 𝑋 → ((𝐹‘𝑦) ⊆ (𝐹‘𝑤) ↔ (𝐹‘𝑋) ⊆ (𝐹‘𝑤)))
30	29	rspcv 3278	. . . . . . . . 9 ⊢ (𝑋 ∈ 𝒫 𝑤 → (∀𝑦 ∈ 𝒫 𝑤(𝐹‘𝑦) ⊆ (𝐹‘𝑤) → (𝐹‘𝑋) ⊆ (𝐹‘𝑤)))
31	19, 27, 30	sylc 63	. . . . . . . 8 ⊢ (((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) ∧ (𝑤 ∈ 𝒫 𝐴 ∧ (𝐹‘𝑤) ⊆ 𝑤)) → (𝐹‘𝑋) ⊆ (𝐹‘𝑤))
32		simprr 792	. . . . . . . 8 ⊢ (((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) ∧ (𝑤 ∈ 𝒫 𝐴 ∧ (𝐹‘𝑤) ⊆ 𝑤)) → (𝐹‘𝑤) ⊆ 𝑤)
33	31, 32	sstrd 3578	. . . . . . 7 ⊢ (((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) ∧ (𝑤 ∈ 𝒫 𝐴 ∧ (𝐹‘𝑤) ⊆ 𝑤)) → (𝐹‘𝑋) ⊆ 𝑤)
34	33	expr 641	. . . . . 6 ⊢ (((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) ∧ 𝑤 ∈ 𝒫 𝐴) → ((𝐹‘𝑤) ⊆ 𝑤 → (𝐹‘𝑋) ⊆ 𝑤))
35	34	ralrimiva 2949	. . . . 5 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → ∀𝑤 ∈ 𝒫 𝐴((𝐹‘𝑤) ⊆ 𝑤 → (𝐹‘𝑋) ⊆ 𝑤))
36		ssintrab 4435	. . . . 5 ⊢ ((𝐹‘𝑋) ⊆ ∩ {𝑤 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑤) ⊆ 𝑤} ↔ ∀𝑤 ∈ 𝒫 𝐴((𝐹‘𝑤) ⊆ 𝑤 → (𝐹‘𝑋) ⊆ 𝑤))
37	35, 36	sylibr 223	. . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → (𝐹‘𝑋) ⊆ ∩ {𝑤 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑤) ⊆ 𝑤})
38	13	cbvrabv 3172	. . . . . 6 ⊢ {𝑧 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑧) ⊆ 𝑧} = {𝑤 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑤) ⊆ 𝑤}
39	38	inteqi 4414	. . . . 5 ⊢ ∩ {𝑧 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑧) ⊆ 𝑧} = ∩ {𝑤 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑤) ⊆ 𝑤}
40	1, 39	eqtri 2632	. . . 4 ⊢ 𝑋 = ∩ {𝑤 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑤) ⊆ 𝑤}
41	37, 40	syl6sseqr 3615	. . 3 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → (𝐹‘𝑋) ⊆ 𝑋)
42		elpw2g 4754	. . . . . . . . . 10 ⊢ (𝐴 ∈ 𝑉 → (𝑋 ∈ 𝒫 𝐴 ↔ 𝑋 ⊆ 𝐴))
43	42	3ad2ant1 1075	. . . . . . . . 9 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → (𝑋 ∈ 𝒫 𝐴 ↔ 𝑋 ⊆ 𝐴))
44	10, 43	mpbird 246	. . . . . . . 8 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → 𝑋 ∈ 𝒫 𝐴)
45		simp3 1056	. . . . . . . . 9 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥))
46		pweq 4111	. . . . . . . . . . 11 ⊢ (𝑥 = 𝐴 → 𝒫 𝑥 = 𝒫 𝐴)
47		fveq2 6103	. . . . . . . . . . . 12 ⊢ (𝑥 = 𝐴 → (𝐹‘𝑥) = (𝐹‘𝐴))
48	47	sseq2d 3596	. . . . . . . . . . 11 ⊢ (𝑥 = 𝐴 → ((𝐹‘𝑦) ⊆ (𝐹‘𝑥) ↔ (𝐹‘𝑦) ⊆ (𝐹‘𝐴)))
49	46, 48	raleqbidv 3129	. . . . . . . . . 10 ⊢ (𝑥 = 𝐴 → (∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥) ↔ ∀𝑦 ∈ 𝒫 𝐴(𝐹‘𝑦) ⊆ (𝐹‘𝐴)))
50	49	rspcv 3278	. . . . . . . . 9 ⊢ (𝐴 ∈ 𝒫 𝐴 → (∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥) → ∀𝑦 ∈ 𝒫 𝐴(𝐹‘𝑦) ⊆ (𝐹‘𝐴)))
51	3, 45, 50	sylc 63	. . . . . . . 8 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → ∀𝑦 ∈ 𝒫 𝐴(𝐹‘𝑦) ⊆ (𝐹‘𝐴))
52	28	sseq1d 3595	. . . . . . . . 9 ⊢ (𝑦 = 𝑋 → ((𝐹‘𝑦) ⊆ (𝐹‘𝐴) ↔ (𝐹‘𝑋) ⊆ (𝐹‘𝐴)))
53	52	rspcv 3278	. . . . . . . 8 ⊢ (𝑋 ∈ 𝒫 𝐴 → (∀𝑦 ∈ 𝒫 𝐴(𝐹‘𝑦) ⊆ (𝐹‘𝐴) → (𝐹‘𝑋) ⊆ (𝐹‘𝐴)))
54	44, 51, 53	sylc 63	. . . . . . 7 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → (𝐹‘𝑋) ⊆ (𝐹‘𝐴))
55	54, 4	sstrd 3578	. . . . . 6 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → (𝐹‘𝑋) ⊆ 𝐴)
56		fvex 6113	. . . . . . 7 ⊢ (𝐹‘𝑋) ∈ V
57	56	elpw 4114	. . . . . 6 ⊢ ((𝐹‘𝑋) ∈ 𝒫 𝐴 ↔ (𝐹‘𝑋) ⊆ 𝐴)
58	55, 57	sylibr 223	. . . . 5 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → (𝐹‘𝑋) ∈ 𝒫 𝐴)
59	56	elpw 4114	. . . . . . 7 ⊢ ((𝐹‘𝑋) ∈ 𝒫 𝑋 ↔ (𝐹‘𝑋) ⊆ 𝑋)
60	41, 59	sylibr 223	. . . . . 6 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → (𝐹‘𝑋) ∈ 𝒫 𝑋)
61		pweq 4111	. . . . . . . . 9 ⊢ (𝑥 = 𝑋 → 𝒫 𝑥 = 𝒫 𝑋)
62		fveq2 6103	. . . . . . . . . 10 ⊢ (𝑥 = 𝑋 → (𝐹‘𝑥) = (𝐹‘𝑋))
63	62	sseq2d 3596	. . . . . . . . 9 ⊢ (𝑥 = 𝑋 → ((𝐹‘𝑦) ⊆ (𝐹‘𝑥) ↔ (𝐹‘𝑦) ⊆ (𝐹‘𝑋)))
64	61, 63	raleqbidv 3129	. . . . . . . 8 ⊢ (𝑥 = 𝑋 → (∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥) ↔ ∀𝑦 ∈ 𝒫 𝑋(𝐹‘𝑦) ⊆ (𝐹‘𝑋)))
65	64	rspcv 3278	. . . . . . 7 ⊢ (𝑋 ∈ 𝒫 𝐴 → (∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥) → ∀𝑦 ∈ 𝒫 𝑋(𝐹‘𝑦) ⊆ (𝐹‘𝑋)))
66	44, 45, 65	sylc 63	. . . . . 6 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → ∀𝑦 ∈ 𝒫 𝑋(𝐹‘𝑦) ⊆ (𝐹‘𝑋))
67		fveq2 6103	. . . . . . . 8 ⊢ (𝑦 = (𝐹‘𝑋) → (𝐹‘𝑦) = (𝐹‘(𝐹‘𝑋)))
68	67	sseq1d 3595	. . . . . . 7 ⊢ (𝑦 = (𝐹‘𝑋) → ((𝐹‘𝑦) ⊆ (𝐹‘𝑋) ↔ (𝐹‘(𝐹‘𝑋)) ⊆ (𝐹‘𝑋)))
69	68	rspcv 3278	. . . . . 6 ⊢ ((𝐹‘𝑋) ∈ 𝒫 𝑋 → (∀𝑦 ∈ 𝒫 𝑋(𝐹‘𝑦) ⊆ (𝐹‘𝑋) → (𝐹‘(𝐹‘𝑋)) ⊆ (𝐹‘𝑋)))
70	60, 66, 69	sylc 63	. . . . 5 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → (𝐹‘(𝐹‘𝑋)) ⊆ (𝐹‘𝑋))
71		fveq2 6103	. . . . . . 7 ⊢ (𝑤 = (𝐹‘𝑋) → (𝐹‘𝑤) = (𝐹‘(𝐹‘𝑋)))
72		id 22	. . . . . . 7 ⊢ (𝑤 = (𝐹‘𝑋) → 𝑤 = (𝐹‘𝑋))
73	71, 72	sseq12d 3597	. . . . . 6 ⊢ (𝑤 = (𝐹‘𝑋) → ((𝐹‘𝑤) ⊆ 𝑤 ↔ (𝐹‘(𝐹‘𝑋)) ⊆ (𝐹‘𝑋)))
74	73	intminss 4438	. . . . 5 ⊢ (((𝐹‘𝑋) ∈ 𝒫 𝐴 ∧ (𝐹‘(𝐹‘𝑋)) ⊆ (𝐹‘𝑋)) → ∩ {𝑤 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑤) ⊆ 𝑤} ⊆ (𝐹‘𝑋))
75	58, 70, 74	syl2anc 691	. . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → ∩ {𝑤 ∈ 𝒫 𝐴 ∣ (𝐹‘𝑤) ⊆ 𝑤} ⊆ (𝐹‘𝑋))
76	40, 75	syl5eqss 3612	. . 3 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → 𝑋 ⊆ (𝐹‘𝑋))
77	41, 76	eqssd 3585	. 2 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → (𝐹‘𝑋) = 𝑋)
78	10, 77	jca 553	1 ⊢ ((𝐴 ∈ 𝑉 ∧ (𝐹‘𝐴) ⊆ 𝐴 ∧ ∀𝑥 ∈ 𝒫 𝐴∀𝑦 ∈ 𝒫 𝑥(𝐹‘𝑦) ⊆ (𝐹‘𝑥)) → (𝑋 ⊆ 𝐴 ∧ (𝐹‘𝑋) = 𝑋))

Syntax hints:   → wi 4   ↔ wb 195   ∧ wa 383   ∧ w3a 1031   = wceq 1475   ∈ wcel 1977  ∀wral 2896  {crab 2900   ⊆ wss 3540  𝒫 cpw 4108  ∩ cint 4410  ‘cfv 5804

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1713  ax-4 1728  ax-5 1827  ax-6 1875  ax-7 1922  ax-10 2006  ax-11 2021  ax-12 2034  ax-13 2234  ax-ext 2590  ax-sep 4709  ax-nul 4717

This theorem depends on definitions:  df-bi 196  df-or 384  df-an 385  df-3an 1033  df-tru 1478  df-ex 1696  df-nf 1701  df-sb 1868  df-eu 2462  df-clab 2597  df-cleq 2603  df-clel 2606  df-nfc 2740  df-ral 2901  df-rex 2902  df-rab 2905  df-v 3175  df-sbc 3403  df-dif 3543  df-un 3545  df-in 3547  df-ss 3554  df-nul 3875  df-if 4037  df-pw 4110  df-sn 4126  df-pr 4128  df-op 4132  df-uni 4373  df-int 4411  df-br 4584  df-iota 5768  df-fv 5812

This theorem is referenced by: (None)