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Mirrors > Home > MPE Home > Th. List > intssuni | Structured version Visualization version GIF version |
Description: The intersection of a nonempty set is a subclass of its union. (Contributed by NM, 29-Jul-2006.) |
Ref | Expression |
---|---|
intssuni | ⊢ (𝐴 ≠ ∅ → ∩ 𝐴 ⊆ ∪ 𝐴) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | r19.2z 4391 | . . . 4 ⊢ ((𝐴 ≠ ∅ ∧ ∀𝑦 ∈ 𝐴 𝑥 ∈ 𝑦) → ∃𝑦 ∈ 𝐴 𝑥 ∈ 𝑦) | |
2 | 1 | ex 416 | . . 3 ⊢ (𝐴 ≠ ∅ → (∀𝑦 ∈ 𝐴 𝑥 ∈ 𝑦 → ∃𝑦 ∈ 𝐴 𝑥 ∈ 𝑦)) |
3 | vex 3404 | . . . 4 ⊢ 𝑥 ∈ V | |
4 | 3 | elint2 4853 | . . 3 ⊢ (𝑥 ∈ ∩ 𝐴 ↔ ∀𝑦 ∈ 𝐴 𝑥 ∈ 𝑦) |
5 | eluni2 4810 | . . 3 ⊢ (𝑥 ∈ ∪ 𝐴 ↔ ∃𝑦 ∈ 𝐴 𝑥 ∈ 𝑦) | |
6 | 2, 4, 5 | 3imtr4g 299 | . 2 ⊢ (𝐴 ≠ ∅ → (𝑥 ∈ ∩ 𝐴 → 𝑥 ∈ ∪ 𝐴)) |
7 | 6 | ssrdv 3893 | 1 ⊢ (𝐴 ≠ ∅ → ∩ 𝐴 ⊆ ∪ 𝐴) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∈ wcel 2114 ≠ wne 2935 ∀wral 3054 ∃wrex 3055 ⊆ wss 3853 ∅c0 4221 ∪ cuni 4806 ∩ cint 4846 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1802 ax-4 1816 ax-5 1917 ax-6 1975 ax-7 2020 ax-8 2116 ax-9 2124 ax-ext 2711 |
This theorem depends on definitions: df-bi 210 df-an 400 df-tru 1545 df-fal 1555 df-ex 1787 df-sb 2075 df-clab 2718 df-cleq 2731 df-clel 2812 df-ne 2936 df-ral 3059 df-rex 3060 df-v 3402 df-dif 3856 df-in 3860 df-ss 3870 df-nul 4222 df-uni 4807 df-int 4847 |
This theorem is referenced by: unissint 4870 intssuni2 4871 intss2 5003 fin23lem31 9855 wunint 10227 tskint 10297 incexc 15297 incexc2 15298 subgint 18433 efgval 18973 lbsextlem3 20063 cssmre 20521 uffixfr 22686 uffix2 22687 uffixsn 22688 ssmxidllem 31225 insiga 31687 dfon2lem8 33352 intidl 35842 elrfi 40128 |
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