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Mirrors > Home > ILE Home > Th. List > ndmfvg | GIF version |
Description: The value of a class outside its domain is the empty set. (Contributed by Jim Kingdon, 15-Jan-2019.) |
Ref | Expression |
---|---|
ndmfvg | ⊢ ((𝐴 ∈ V ∧ ¬ 𝐴 ∈ dom 𝐹) → (𝐹‘𝐴) = ∅) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | euex 1985 | . . . . 5 ⊢ (∃!𝑥 𝐴𝐹𝑥 → ∃𝑥 𝐴𝐹𝑥) | |
2 | eldmg 4662 | . . . . 5 ⊢ (𝐴 ∈ V → (𝐴 ∈ dom 𝐹 ↔ ∃𝑥 𝐴𝐹𝑥)) | |
3 | 1, 2 | syl5ibr 155 | . . . 4 ⊢ (𝐴 ∈ V → (∃!𝑥 𝐴𝐹𝑥 → 𝐴 ∈ dom 𝐹)) |
4 | 3 | con3d 599 | . . 3 ⊢ (𝐴 ∈ V → (¬ 𝐴 ∈ dom 𝐹 → ¬ ∃!𝑥 𝐴𝐹𝑥)) |
5 | tz6.12-2 5331 | . . 3 ⊢ (¬ ∃!𝑥 𝐴𝐹𝑥 → (𝐹‘𝐴) = ∅) | |
6 | 4, 5 | syl6 33 | . 2 ⊢ (𝐴 ∈ V → (¬ 𝐴 ∈ dom 𝐹 → (𝐹‘𝐴) = ∅)) |
7 | 6 | imp 123 | 1 ⊢ ((𝐴 ∈ V ∧ ¬ 𝐴 ∈ dom 𝐹) → (𝐹‘𝐴) = ∅) |
Colors of variables: wff set class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 103 = wceq 1296 ∃wex 1433 ∈ wcel 1445 ∃!weu 1955 Vcvv 2633 ∅c0 3302 class class class wbr 3867 dom cdm 4467 ‘cfv 5049 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-in1 582 ax-in2 583 ax-io 668 ax-5 1388 ax-7 1389 ax-gen 1390 ax-ie1 1434 ax-ie2 1435 ax-8 1447 ax-10 1448 ax-11 1449 ax-i12 1450 ax-bndl 1451 ax-4 1452 ax-17 1471 ax-i9 1475 ax-ial 1479 ax-i5r 1480 ax-ext 2077 |
This theorem depends on definitions: df-bi 116 df-3an 929 df-tru 1299 df-fal 1302 df-nf 1402 df-sb 1700 df-eu 1958 df-clab 2082 df-cleq 2088 df-clel 2091 df-nfc 2224 df-ral 2375 df-rex 2376 df-v 2635 df-dif 3015 df-un 3017 df-in 3019 df-ss 3026 df-nul 3303 df-sn 3472 df-pr 3473 df-op 3475 df-uni 3676 df-br 3868 df-dm 4477 df-iota 5014 df-fv 5057 |
This theorem is referenced by: ovprc 5722 sumnul 10967 |
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