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Mirrors > Home > MPE Home > Th. List > Mathboxes > disjss1f | Structured version Visualization version GIF version |
Description: A subset of a disjoint collection is disjoint. (Contributed by Thierry Arnoux, 6-Apr-2017.) |
Ref | Expression |
---|---|
disjss1f.1 | ⊢ Ⅎ𝑥𝐴 |
disjss1f.2 | ⊢ Ⅎ𝑥𝐵 |
Ref | Expression |
---|---|
disjss1f | ⊢ (𝐴 ⊆ 𝐵 → (Disj 𝑥 ∈ 𝐵 𝐶 → Disj 𝑥 ∈ 𝐴 𝐶)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | disjss1f.1 | . . . 4 ⊢ Ⅎ𝑥𝐴 | |
2 | disjss1f.2 | . . . 4 ⊢ Ⅎ𝑥𝐵 | |
3 | 1, 2 | ssrmof 4029 | . . 3 ⊢ (𝐴 ⊆ 𝐵 → (∃*𝑥 ∈ 𝐵 𝑦 ∈ 𝐶 → ∃*𝑥 ∈ 𝐴 𝑦 ∈ 𝐶)) |
4 | 3 | alimdv 1908 | . 2 ⊢ (𝐴 ⊆ 𝐵 → (∀𝑦∃*𝑥 ∈ 𝐵 𝑦 ∈ 𝐶 → ∀𝑦∃*𝑥 ∈ 𝐴 𝑦 ∈ 𝐶)) |
5 | df-disj 5023 | . 2 ⊢ (Disj 𝑥 ∈ 𝐵 𝐶 ↔ ∀𝑦∃*𝑥 ∈ 𝐵 𝑦 ∈ 𝐶) | |
6 | df-disj 5023 | . 2 ⊢ (Disj 𝑥 ∈ 𝐴 𝐶 ↔ ∀𝑦∃*𝑥 ∈ 𝐴 𝑦 ∈ 𝐶) | |
7 | 4, 5, 6 | 3imtr4g 297 | 1 ⊢ (𝐴 ⊆ 𝐵 → (Disj 𝑥 ∈ 𝐵 𝐶 → Disj 𝑥 ∈ 𝐴 𝐶)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∀wal 1526 ∈ wcel 2105 Ⅎwnfc 2958 ∃*wrmo 3138 ⊆ wss 3933 Disj wdisj 5022 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1787 ax-4 1801 ax-5 1902 ax-6 1961 ax-7 2006 ax-8 2107 ax-9 2115 ax-10 2136 ax-11 2151 ax-12 2167 ax-ext 2790 |
This theorem depends on definitions: df-bi 208 df-an 397 df-or 842 df-tru 1531 df-ex 1772 df-nf 1776 df-sb 2061 df-mo 2615 df-clab 2797 df-cleq 2811 df-clel 2890 df-nfc 2960 df-rmo 3143 df-in 3940 df-ss 3949 df-disj 5023 |
This theorem is referenced by: disjeq1f 30251 esumrnmpt2 31226 measvuni 31372 |
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