| Mathbox for Zhi Wang |
< Previous
Next >
Nearby theorems |
||
| 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 4312 | . 2 ⊢ (𝐴 ∈ (𝐹‘𝐵) → (𝐹‘𝐵) ≠ ∅) | |
| 2 | fveq1 6864 | . . . 4 ⊢ (𝐹 = ∅ → (𝐹‘𝐵) = (∅‘𝐵)) | |
| 3 | 0fv 6909 | . . . 4 ⊢ (∅‘𝐵) = ∅ | |
| 4 | 2, 3 | eqtrdi 2781 | . . 3 ⊢ (𝐹 = ∅ → (𝐹‘𝐵) = ∅) |
| 5 | 4 | necon3i 2959 | . 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 1540 ∈ wcel 2109 ≠ wne 2927 ∅c0 4304 ‘cfv 6519 |
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1795 ax-4 1809 ax-5 1910 ax-6 1967 ax-7 2008 ax-8 2111 ax-9 2119 ax-10 2142 ax-11 2158 ax-12 2178 ax-ext 2702 ax-nul 5269 ax-pr 5395 |
| This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3an 1088 df-tru 1543 df-fal 1553 df-ex 1780 df-nf 1784 df-sb 2066 df-mo 2534 df-eu 2563 df-clab 2709 df-cleq 2722 df-clel 2804 df-ne 2928 df-ral 3047 df-rex 3056 df-rab 3412 df-v 3457 df-dif 3925 df-un 3927 df-ss 3939 df-nul 4305 df-if 4497 df-sn 4598 df-pr 4600 df-op 4604 df-uni 4880 df-br 5116 df-dm 5656 df-iota 6472 df-fv 6527 |
| This theorem is referenced by: neircl 48821 sectrcl 48939 invrcl 48941 isorcl 48950 catcrcl 49287 |
| Copyright terms: Public domain | W3C validator |