Theorem bj-restuni2 35325

Description: The union of an elementwise intersection on a family of sets by a subset is equal to that subset. See also restuni 22385 and restuni2 22390. (Contributed by BJ, 27-Apr-2021.)

Assertion

Ref	Expression
bj-restuni2	⊢ ((𝑋 ∈ 𝑉 ∧ 𝐴 ⊆ ∪ 𝑋) → ∪ (𝑋 ↾t 𝐴) = 𝐴)

Proof of Theorem bj-restuni2

Step	Hyp	Ref	Expression
1		uniexg 7633	. . . . 5 ⊢ (𝑋 ∈ 𝑉 → ∪ 𝑋 ∈ V)
2		ssexg 5262	. . . . 5 ⊢ ((𝐴 ⊆ ∪ 𝑋 ∧ ∪ 𝑋 ∈ V) → 𝐴 ∈ V)
3	1, 2	sylan2 593	. . . 4 ⊢ ((𝐴 ⊆ ∪ 𝑋 ∧ 𝑋 ∈ 𝑉) → 𝐴 ∈ V)
4	3	ancoms 459	. . 3 ⊢ ((𝑋 ∈ 𝑉 ∧ 𝐴 ⊆ ∪ 𝑋) → 𝐴 ∈ V)
5		bj-restuni 35324	. . 3 ⊢ ((𝑋 ∈ 𝑉 ∧ 𝐴 ∈ V) → ∪ (𝑋 ↾t 𝐴) = (∪ 𝑋 ∩ 𝐴))
6	4, 5	syldan 591	. 2 ⊢ ((𝑋 ∈ 𝑉 ∧ 𝐴 ⊆ ∪ 𝑋) → ∪ (𝑋 ↾t 𝐴) = (∪ 𝑋 ∩ 𝐴))
7		inss2 4174	. . . . 5 ⊢ (∪ 𝑋 ∩ 𝐴) ⊆ 𝐴
8	7	a1i 11	. . . 4 ⊢ (𝐴 ⊆ ∪ 𝑋 → (∪ 𝑋 ∩ 𝐴) ⊆ 𝐴)
9		id 22	. . . . 5 ⊢ (𝐴 ⊆ ∪ 𝑋 → 𝐴 ⊆ ∪ 𝑋)
10		ssidd 3954	. . . . 5 ⊢ (𝐴 ⊆ ∪ 𝑋 → 𝐴 ⊆ 𝐴)
11	9, 10	ssind 4177	. . . 4 ⊢ (𝐴 ⊆ ∪ 𝑋 → 𝐴 ⊆ (∪ 𝑋 ∩ 𝐴))
12	8, 11	eqssd 3948	. . 3 ⊢ (𝐴 ⊆ ∪ 𝑋 → (∪ 𝑋 ∩ 𝐴) = 𝐴)
13	12	adantl 482	. 2 ⊢ ((𝑋 ∈ 𝑉 ∧ 𝐴 ⊆ ∪ 𝑋) → (∪ 𝑋 ∩ 𝐴) = 𝐴)
14	6, 13	eqtrd 2777	1 ⊢ ((𝑋 ∈ 𝑉 ∧ 𝐴 ⊆ ∪ 𝑋) → ∪ (𝑋 ↾t 𝐴) = 𝐴)

Syntax hints:   → wi 4   ∧ wa 396   = wceq 1540   ∈ wcel 2105  Vcvv 3441   ∩ cin 3896   ⊆ wss 3897  ∪ cuni 4850  (class class class)co 7315   ↾_t crest 17201

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1796  ax-4 1810  ax-5 1912  ax-6 1970  ax-7 2010  ax-8 2107  ax-9 2115  ax-10 2136  ax-11 2153  ax-12 2170  ax-ext 2708  ax-rep 5224  ax-sep 5238  ax-nul 5245  ax-pr 5367  ax-un 7628

This theorem depends on definitions:  df-bi 206  df-an 397  df-or 845  df-3an 1088  df-tru 1543  df-fal 1553  df-ex 1781  df-nf 1785  df-sb 2067  df-mo 2539  df-eu 2568  df-clab 2715  df-cleq 2729  df-clel 2815  df-nfc 2887  df-ne 2942  df-ral 3063  df-rex 3072  df-reu 3351  df-rab 3405  df-v 3443  df-sbc 3727  df-csb 3843  df-dif 3900  df-un 3902  df-in 3904  df-ss 3914  df-nul 4268  df-if 4472  df-sn 4572  df-pr 4574  df-op 4578  df-uni 4851  df-iun 4939  df-br 5088  df-opab 5150  df-mpt 5171  df-id 5507  df-xp 5613  df-rel 5614  df-cnv 5615  df-co 5616  df-dm 5617  df-rn 5618  df-res 5619  df-ima 5620  df-iota 6417  df-fun 6467  df-fn 6468  df-f 6469  df-f1 6470  df-fo 6471  df-f1o 6472  df-fv 6473  df-ov 7318  df-oprab 7319  df-mpo 7320  df-rest 17203

This theorem is referenced by: (None)