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Mirrors > Home > MPE Home > Th. List > funconstss | Structured version Visualization version GIF version |
Description: Two ways of specifying that a function is constant on a subdomain. (Contributed by NM, 8-Mar-2007.) |
Ref | Expression |
---|---|
funconstss | ⊢ ((Fun 𝐹 ∧ 𝐴 ⊆ dom 𝐹) → (∀𝑥 ∈ 𝐴 (𝐹‘𝑥) = 𝐵 ↔ 𝐴 ⊆ (◡𝐹 “ {𝐵}))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | funimass4 6907 | . . 3 ⊢ ((Fun 𝐹 ∧ 𝐴 ⊆ dom 𝐹) → ((𝐹 “ 𝐴) ⊆ {𝐵} ↔ ∀𝑥 ∈ 𝐴 (𝐹‘𝑥) ∈ {𝐵})) | |
2 | fvex 6855 | . . . . 5 ⊢ (𝐹‘𝑥) ∈ V | |
3 | 2 | elsn 4601 | . . . 4 ⊢ ((𝐹‘𝑥) ∈ {𝐵} ↔ (𝐹‘𝑥) = 𝐵) |
4 | 3 | ralbii 3096 | . . 3 ⊢ (∀𝑥 ∈ 𝐴 (𝐹‘𝑥) ∈ {𝐵} ↔ ∀𝑥 ∈ 𝐴 (𝐹‘𝑥) = 𝐵) |
5 | 1, 4 | bitr2di 287 | . 2 ⊢ ((Fun 𝐹 ∧ 𝐴 ⊆ dom 𝐹) → (∀𝑥 ∈ 𝐴 (𝐹‘𝑥) = 𝐵 ↔ (𝐹 “ 𝐴) ⊆ {𝐵})) |
6 | funimass3 7004 | . 2 ⊢ ((Fun 𝐹 ∧ 𝐴 ⊆ dom 𝐹) → ((𝐹 “ 𝐴) ⊆ {𝐵} ↔ 𝐴 ⊆ (◡𝐹 “ {𝐵}))) | |
7 | 5, 6 | bitrd 278 | 1 ⊢ ((Fun 𝐹 ∧ 𝐴 ⊆ dom 𝐹) → (∀𝑥 ∈ 𝐴 (𝐹‘𝑥) = 𝐵 ↔ 𝐴 ⊆ (◡𝐹 “ {𝐵}))) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 205 ∧ wa 396 = wceq 1541 ∈ wcel 2106 ∀wral 3064 ⊆ wss 3910 {csn 4586 ◡ccnv 5632 dom cdm 5633 “ cima 5636 Fun wfun 6490 ‘cfv 6496 |
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 1913 ax-6 1971 ax-7 2011 ax-8 2108 ax-9 2116 ax-10 2137 ax-11 2154 ax-12 2171 ax-ext 2707 ax-sep 5256 ax-nul 5263 ax-pr 5384 |
This theorem depends on definitions: df-bi 206 df-an 397 df-or 846 df-3an 1089 df-tru 1544 df-fal 1554 df-ex 1782 df-nf 1786 df-sb 2068 df-mo 2538 df-eu 2567 df-clab 2714 df-cleq 2728 df-clel 2814 df-ne 2944 df-ral 3065 df-rex 3074 df-rab 3408 df-v 3447 df-dif 3913 df-un 3915 df-in 3917 df-ss 3927 df-nul 4283 df-if 4487 df-sn 4587 df-pr 4589 df-op 4593 df-uni 4866 df-br 5106 df-opab 5168 df-id 5531 df-xp 5639 df-rel 5640 df-cnv 5641 df-co 5642 df-dm 5643 df-rn 5644 df-res 5645 df-ima 5646 df-iota 6448 df-fun 6498 df-fn 6499 df-fv 6504 |
This theorem is referenced by: fconst3 7163 ipasslem8 29779 |
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