| Mathbox for Alexander van der Vekens |
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| Mirrors > Home > MPE Home > Th. List > Mathboxes > preimafvn0 | Structured version Visualization version GIF version | ||
| Description: The preimage of a function value is not empty. (Contributed by AV, 7-Mar-2024.) |
| Ref | Expression |
|---|---|
| preimafvn0 | ⊢ ((𝐹 Fn 𝐴 ∧ 𝑋 ∈ 𝐴) → (◡𝐹 “ {(𝐹‘𝑋)}) ≠ ∅) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | preimafvsnel 47990 | . 2 ⊢ ((𝐹 Fn 𝐴 ∧ 𝑋 ∈ 𝐴) → 𝑋 ∈ (◡𝐹 “ {(𝐹‘𝑋)})) | |
| 2 | 1 | ne0d 4296 | 1 ⊢ ((𝐹 Fn 𝐴 ∧ 𝑋 ∈ 𝐴) → (◡𝐹 “ {(𝐹‘𝑋)}) ≠ ∅) |
| Colors of variables: wff setvar class |
| Syntax hints: → wi 4 ∧ wa 399 ∈ wcel 2144 ≠ wne 2959 ∅c0 4287 {csn 4584 ◡ccnv 5648 “ cima 5652 Fn wfn 6518 ‘cfv 6523 |
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1817 ax-4 1831 ax-5 1932 ax-6 1989 ax-7 2030 ax-8 2146 ax-9 2154 ax-10 2177 ax-12 2214 ax-ext 2736 ax-sep 5248 ax-nul 5258 ax-pr 5392 |
| This theorem depends on definitions: df-bi 209 df-an 400 df-or 859 df-3an 1101 df-tru 1565 df-fal 1575 df-ex 1802 df-nf 1806 df-sb 2093 df-mo 2568 df-eu 2598 df-clab 2743 df-cleq 2756 df-clel 2839 df-ne 2960 df-ral 3079 df-rex 3089 df-rab 3417 df-v 3458 df-dif 3909 df-un 3911 df-in 3913 df-ss 3923 df-nul 4288 df-if 4483 df-sn 4585 df-pr 4587 df-op 4591 df-uni 4868 df-br 5103 df-opab 5165 df-id 5544 df-xp 5655 df-rel 5656 df-cnv 5657 df-co 5658 df-dm 5659 df-rn 5660 df-res 5661 df-ima 5662 df-iota 6479 df-fun 6525 df-fn 6526 df-fv 6531 |
| This theorem is referenced by: (None) |
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