Intuitionistic Logic Explorer |
< Previous
Next >
Nearby theorems |
||
Mirrors > Home > ILE Home > Th. List > ddifss | GIF version |
Description: Double complement under universal class. In classical logic (or given an additional hypothesis, as in ddifnel 3177), this is equality rather than subset. (Contributed by Jim Kingdon, 24-Jul-2018.) |
Ref | Expression |
---|---|
ddifss | ⊢ 𝐴 ⊆ (V ∖ (V ∖ 𝐴)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ssv 3089 | . 2 ⊢ 𝐴 ⊆ V | |
2 | ssddif 3280 | . 2 ⊢ (𝐴 ⊆ V ↔ 𝐴 ⊆ (V ∖ (V ∖ 𝐴))) | |
3 | 1, 2 | mpbi 144 | 1 ⊢ 𝐴 ⊆ (V ∖ (V ∖ 𝐴)) |
Colors of variables: wff set class |
Syntax hints: Vcvv 2660 ∖ cdif 3038 ⊆ wss 3041 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-in1 588 ax-in2 589 ax-io 683 ax-5 1408 ax-7 1409 ax-gen 1410 ax-ie1 1454 ax-ie2 1455 ax-8 1467 ax-10 1468 ax-11 1469 ax-i12 1470 ax-bndl 1471 ax-4 1472 ax-17 1491 ax-i9 1495 ax-ial 1499 ax-i5r 1500 ax-ext 2099 |
This theorem depends on definitions: df-bi 116 df-tru 1319 df-nf 1422 df-sb 1721 df-clab 2104 df-cleq 2110 df-clel 2113 df-nfc 2247 df-v 2662 df-dif 3043 df-in 3047 df-ss 3054 |
This theorem is referenced by: ssindif0im 3392 difdifdirss 3417 |
Copyright terms: Public domain | W3C validator |