Metamath Proof Explorer |
< Previous
Next >
Nearby theorems |
||
Mirrors > Home > MPE Home > Th. List > oninton | Structured version Visualization version GIF version |
Description: The intersection of a nonempty collection of ordinal numbers is an ordinal number. Compare Exercise 6 of [TakeutiZaring] p. 44. (Contributed by NM, 29-Jan-1997.) |
Ref | Expression |
---|---|
oninton | ⊢ ((𝐴 ⊆ On ∧ 𝐴 ≠ ∅) → ∩ 𝐴 ∈ On) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | onint 7504 | . . . 4 ⊢ ((𝐴 ⊆ On ∧ 𝐴 ≠ ∅) → ∩ 𝐴 ∈ 𝐴) | |
2 | 1 | ex 415 | . . 3 ⊢ (𝐴 ⊆ On → (𝐴 ≠ ∅ → ∩ 𝐴 ∈ 𝐴)) |
3 | ssel 3960 | . . 3 ⊢ (𝐴 ⊆ On → (∩ 𝐴 ∈ 𝐴 → ∩ 𝐴 ∈ On)) | |
4 | 2, 3 | syld 47 | . 2 ⊢ (𝐴 ⊆ On → (𝐴 ≠ ∅ → ∩ 𝐴 ∈ On)) |
5 | 4 | imp 409 | 1 ⊢ ((𝐴 ⊆ On ∧ 𝐴 ≠ ∅) → ∩ 𝐴 ∈ On) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 398 ∈ wcel 2110 ≠ wne 3016 ⊆ wss 3935 ∅c0 4290 ∩ cint 4868 Oncon0 6185 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1907 ax-6 1966 ax-7 2011 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2157 ax-12 2173 ax-ext 2793 ax-sep 5195 ax-nul 5202 ax-pr 5321 ax-un 7455 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3or 1084 df-3an 1085 df-tru 1536 df-ex 1777 df-nf 1781 df-sb 2066 df-mo 2618 df-eu 2650 df-clab 2800 df-cleq 2814 df-clel 2893 df-nfc 2963 df-ne 3017 df-ral 3143 df-rex 3144 df-rab 3147 df-v 3496 df-sbc 3772 df-dif 3938 df-un 3940 df-in 3942 df-ss 3951 df-pss 3953 df-nul 4291 df-if 4467 df-sn 4561 df-pr 4563 df-tp 4565 df-op 4567 df-uni 4832 df-int 4869 df-br 5059 df-opab 5121 df-tr 5165 df-eprel 5459 df-po 5468 df-so 5469 df-fr 5508 df-we 5510 df-ord 6188 df-on 6189 |
This theorem is referenced by: onintrab 7510 onnmin 7512 onminex 7516 onmindif2 7521 iinon 7971 oawordeulem 8174 nnawordex 8257 tz9.12lem1 9210 rankf 9217 cardf2 9366 cff 9664 coftr 9689 sltval2 33158 nocvxminlem 33242 dnnumch3lem 39639 dnnumch3 39640 |
Copyright terms: Public domain | W3C validator |