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| Mirrors > Home > MPE Home > Th. List > Mathboxes > elfvne0 | Structured version Visualization version GIF version | ||
| Description: If a function value has a member, then the function is not an empty set (An artifact of our function value definition.) (Contributed by Zhi Wang, 16-Sep-2024.) |
| Ref | Expression |
|---|---|
| elfvne0 | ⊢ (𝐴 ∈ (𝐹‘𝐵) → 𝐹 ≠ ∅) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ne0i 4295 | . 2 ⊢ (𝐴 ∈ (𝐹‘𝐵) → (𝐹‘𝐵) ≠ ∅) | |
| 2 | fveq1 6841 | . . . 4 ⊢ (𝐹 = ∅ → (𝐹‘𝐵) = (∅‘𝐵)) | |
| 3 | 0fv 6883 | . . . 4 ⊢ (∅‘𝐵) = ∅ | |
| 4 | 2, 3 | eqtrdi 2788 | . . 3 ⊢ (𝐹 = ∅ → (𝐹‘𝐵) = ∅) |
| 5 | 4 | necon3i 2965 | . 2 ⊢ ((𝐹‘𝐵) ≠ ∅ → 𝐹 ≠ ∅) |
| 6 | 1, 5 | syl 17 | 1 ⊢ (𝐴 ∈ (𝐹‘𝐵) → 𝐹 ≠ ∅) |
| Colors of variables: wff setvar class |
| Syntax hints: → wi 4 = wceq 1542 ∈ wcel 2114 ≠ wne 2933 ∅c0 4287 ‘cfv 6500 |
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1912 ax-6 1969 ax-7 2010 ax-8 2116 ax-9 2124 ax-ext 2709 ax-nul 5253 ax-pr 5379 |
| This theorem depends on definitions: df-bi 207 df-an 396 df-or 849 df-3an 1089 df-tru 1545 df-fal 1555 df-ex 1782 df-sb 2069 df-mo 2540 df-eu 2570 df-clab 2716 df-cleq 2729 df-clel 2812 df-ne 2934 df-rab 3402 df-v 3444 df-dif 3906 df-un 3908 df-ss 3920 df-nul 4288 df-if 4482 df-sn 4583 df-pr 4585 df-op 4589 df-uni 4866 df-br 5101 df-dm 5642 df-iota 6456 df-fv 6508 |
| This theorem is referenced by: neircl 49264 sectrcl 49381 invrcl 49383 isorcl 49392 catcrcl 49754 |
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