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Mirrors > Home > MPE Home > Th. List > df-iin | Structured version Visualization version GIF version |
Description: Define indexed intersection. Definition of [Stoll] p. 45. See the remarks for its sibling operation of indexed union df-iun 4522. An alternate definition tying indexed intersection to ordinary intersection is dfiin2 4555. Theorem intiin 4574 provides a definition of ordinary intersection in terms of indexed intersection. (Contributed by NM, 27-Jun-1998.) |
Ref | Expression |
---|---|
df-iin | ⊢ ∩ 𝑥 ∈ 𝐴 𝐵 = {𝑦 ∣ ∀𝑥 ∈ 𝐴 𝑦 ∈ 𝐵} |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | vx | . . 3 setvar 𝑥 | |
2 | cA | . . 3 class 𝐴 | |
3 | cB | . . 3 class 𝐵 | |
4 | 1, 2, 3 | ciin 4521 | . 2 class ∩ 𝑥 ∈ 𝐴 𝐵 |
5 | vy | . . . . . 6 setvar 𝑦 | |
6 | 5 | cv 1482 | . . . . 5 class 𝑦 |
7 | 6, 3 | wcel 1990 | . . . 4 wff 𝑦 ∈ 𝐵 |
8 | 7, 1, 2 | wral 2912 | . . 3 wff ∀𝑥 ∈ 𝐴 𝑦 ∈ 𝐵 |
9 | 8, 5 | cab 2608 | . 2 class {𝑦 ∣ ∀𝑥 ∈ 𝐴 𝑦 ∈ 𝐵} |
10 | 4, 9 | wceq 1483 | 1 wff ∩ 𝑥 ∈ 𝐴 𝐵 = {𝑦 ∣ ∀𝑥 ∈ 𝐴 𝑦 ∈ 𝐵} |
Colors of variables: wff setvar class |
This definition is referenced by: eliin 4525 iineq1 4535 iineq2 4538 nfiin 4549 nfii1 4551 dfiin2g 4553 cbviin 4558 intiin 4574 0iin 4578 viin 4579 iinxsng 4600 iinxprg 4601 iinuni 4609 iineq12f 33973 |
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