Theorem inunissunidif 38080

Description: Theorem about subsets of the difference of unions. (Contributed by ML, 29-Mar-2021.)

Assertion

Ref	Expression
inunissunidif	⊢ ((𝐴 ∩ ∪ 𝐶) = ∅ → (𝐴 ⊆ ∪ 𝐵 ↔ 𝐴 ⊆ ∪ (𝐵 ∖ 𝐶)))

Proof of Theorem inunissunidif

Step	Hyp	Ref	Expression
1		reldisj 4413	. . . 4 ⊢ (𝐴 ⊆ ∪ 𝐵 → ((𝐴 ∩ ∪ 𝐶) = ∅ ↔ 𝐴 ⊆ (∪ 𝐵 ∖ ∪ 𝐶)))
2		difunieq 38079	. . . . 5 ⊢ (∪ 𝐵 ∖ ∪ 𝐶) ⊆ ∪ (𝐵 ∖ 𝐶)
3		sstr 3946	. . . . 5 ⊢ ((𝐴 ⊆ (∪ 𝐵 ∖ ∪ 𝐶) ∧ (∪ 𝐵 ∖ ∪ 𝐶) ⊆ ∪ (𝐵 ∖ 𝐶)) → 𝐴 ⊆ ∪ (𝐵 ∖ 𝐶))
4	2, 3	mpan2 704	. . . 4 ⊢ (𝐴 ⊆ (∪ 𝐵 ∖ ∪ 𝐶) → 𝐴 ⊆ ∪ (𝐵 ∖ 𝐶))
5	1, 4	biimtrdi 256	. . 3 ⊢ (𝐴 ⊆ ∪ 𝐵 → ((𝐴 ∩ ∪ 𝐶) = ∅ → 𝐴 ⊆ ∪ (𝐵 ∖ 𝐶)))
6	5	com12 33	. 2 ⊢ ((𝐴 ∩ ∪ 𝐶) = ∅ → (𝐴 ⊆ ∪ 𝐵 → 𝐴 ⊆ ∪ (𝐵 ∖ 𝐶)))
7		difss 4090	. . . 4 ⊢ (𝐵 ∖ 𝐶) ⊆ 𝐵
8	7	unissi 4883	. . 3 ⊢ ∪ (𝐵 ∖ 𝐶) ⊆ ∪ 𝐵
9		sstr 3946	. . 3 ⊢ ((𝐴 ⊆ ∪ (𝐵 ∖ 𝐶) ∧ ∪ (𝐵 ∖ 𝐶) ⊆ ∪ 𝐵) → 𝐴 ⊆ ∪ 𝐵)
10	8, 9	mpan2 704	. 2 ⊢ (𝐴 ⊆ ∪ (𝐵 ∖ 𝐶) → 𝐴 ⊆ ∪ 𝐵)
11	6, 10	impbid1 228	1 ⊢ ((𝐴 ∩ ∪ 𝐶) = ∅ → (𝐴 ⊆ ∪ 𝐵 ↔ 𝐴 ⊆ ∪ (𝐵 ∖ 𝐶)))

This proof depends on syntax axioms:   → wi 4   ↔ wb 209   = wceq 1570   ∖ cdif 3903   ∩ cin 3905   ⊆ wss 3906  ∅c0 4286  ∪ cuni 4874

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2148  ax-9 2156  ax-10 2179  ax-12 2216  ax-ext 2737

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-tru 1573  df-fal 1583  df-ex 1813  df-nf 1817  df-sb 2100  df-clab 2744  df-cleq 2757  df-clel 2840  df-ral 3082  df-v 3459  df-dif 3909  df-in 3913  df-ss 3923  df-nul 4287  df-uni 4875

This theorem is used by:  pibt2  38122