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Mirrors > Home > MPE Home > Th. List > fzprval | Structured version Visualization version GIF version |
Description: Two ways of defining the first two values of a sequence on ℕ. (Contributed by NM, 5-Sep-2011.) |
Ref | Expression |
---|---|
fzprval | ⊢ (∀𝑥 ∈ (1...2)(𝐹‘𝑥) = if(𝑥 = 1, 𝐴, 𝐵) ↔ ((𝐹‘1) = 𝐴 ∧ (𝐹‘2) = 𝐵)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | fz12pr 12958 | . . 3 ⊢ (1...2) = {1, 2} | |
2 | 1 | raleqi 3413 | . 2 ⊢ (∀𝑥 ∈ (1...2)(𝐹‘𝑥) = if(𝑥 = 1, 𝐴, 𝐵) ↔ ∀𝑥 ∈ {1, 2} (𝐹‘𝑥) = if(𝑥 = 1, 𝐴, 𝐵)) |
3 | 1ex 10631 | . . 3 ⊢ 1 ∈ V | |
4 | 2ex 11708 | . . 3 ⊢ 2 ∈ V | |
5 | fveq2 6664 | . . . 4 ⊢ (𝑥 = 1 → (𝐹‘𝑥) = (𝐹‘1)) | |
6 | iftrue 4472 | . . . 4 ⊢ (𝑥 = 1 → if(𝑥 = 1, 𝐴, 𝐵) = 𝐴) | |
7 | 5, 6 | eqeq12d 2837 | . . 3 ⊢ (𝑥 = 1 → ((𝐹‘𝑥) = if(𝑥 = 1, 𝐴, 𝐵) ↔ (𝐹‘1) = 𝐴)) |
8 | fveq2 6664 | . . . 4 ⊢ (𝑥 = 2 → (𝐹‘𝑥) = (𝐹‘2)) | |
9 | 1ne2 11839 | . . . . . . . 8 ⊢ 1 ≠ 2 | |
10 | 9 | necomi 3070 | . . . . . . 7 ⊢ 2 ≠ 1 |
11 | pm13.181 3099 | . . . . . . 7 ⊢ ((𝑥 = 2 ∧ 2 ≠ 1) → 𝑥 ≠ 1) | |
12 | 10, 11 | mpan2 689 | . . . . . 6 ⊢ (𝑥 = 2 → 𝑥 ≠ 1) |
13 | 12 | neneqd 3021 | . . . . 5 ⊢ (𝑥 = 2 → ¬ 𝑥 = 1) |
14 | 13 | iffalsed 4477 | . . . 4 ⊢ (𝑥 = 2 → if(𝑥 = 1, 𝐴, 𝐵) = 𝐵) |
15 | 8, 14 | eqeq12d 2837 | . . 3 ⊢ (𝑥 = 2 → ((𝐹‘𝑥) = if(𝑥 = 1, 𝐴, 𝐵) ↔ (𝐹‘2) = 𝐵)) |
16 | 3, 4, 7, 15 | ralpr 4629 | . 2 ⊢ (∀𝑥 ∈ {1, 2} (𝐹‘𝑥) = if(𝑥 = 1, 𝐴, 𝐵) ↔ ((𝐹‘1) = 𝐴 ∧ (𝐹‘2) = 𝐵)) |
17 | 2, 16 | bitri 277 | 1 ⊢ (∀𝑥 ∈ (1...2)(𝐹‘𝑥) = if(𝑥 = 1, 𝐴, 𝐵) ↔ ((𝐹‘1) = 𝐴 ∧ (𝐹‘2) = 𝐵)) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 208 ∧ wa 398 = wceq 1533 ≠ wne 3016 ∀wral 3138 ifcif 4466 {cpr 4562 ‘cfv 6349 (class class class)co 7150 1c1 10532 2c2 11686 ...cfz 12886 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1907 ax-6 1966 ax-7 2011 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2157 ax-12 2173 ax-ext 2793 ax-sep 5195 ax-nul 5202 ax-pow 5258 ax-pr 5321 ax-un 7455 ax-cnex 10587 ax-resscn 10588 ax-1cn 10589 ax-icn 10590 ax-addcl 10591 ax-addrcl 10592 ax-mulcl 10593 ax-mulrcl 10594 ax-mulcom 10595 ax-addass 10596 ax-mulass 10597 ax-distr 10598 ax-i2m1 10599 ax-1ne0 10600 ax-1rid 10601 ax-rnegex 10602 ax-rrecex 10603 ax-cnre 10604 ax-pre-lttri 10605 ax-pre-lttrn 10606 ax-pre-ltadd 10607 ax-pre-mulgt0 10608 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3or 1084 df-3an 1085 df-tru 1536 df-ex 1777 df-nf 1781 df-sb 2066 df-mo 2618 df-eu 2650 df-clab 2800 df-cleq 2814 df-clel 2893 df-nfc 2963 df-ne 3017 df-nel 3124 df-ral 3143 df-rex 3144 df-reu 3145 df-rab 3147 df-v 3496 df-sbc 3772 df-csb 3883 df-dif 3938 df-un 3940 df-in 3942 df-ss 3951 df-pss 3953 df-nul 4291 df-if 4467 df-pw 4540 df-sn 4561 df-pr 4563 df-tp 4565 df-op 4567 df-uni 4832 df-iun 4913 df-br 5059 df-opab 5121 df-mpt 5139 df-tr 5165 df-id 5454 df-eprel 5459 df-po 5468 df-so 5469 df-fr 5508 df-we 5510 df-xp 5555 df-rel 5556 df-cnv 5557 df-co 5558 df-dm 5559 df-rn 5560 df-res 5561 df-ima 5562 df-pred 6142 df-ord 6188 df-on 6189 df-lim 6190 df-suc 6191 df-iota 6308 df-fun 6351 df-fn 6352 df-f 6353 df-f1 6354 df-fo 6355 df-f1o 6356 df-fv 6357 df-riota 7108 df-ov 7153 df-oprab 7154 df-mpo 7155 df-om 7575 df-1st 7683 df-2nd 7684 df-wrecs 7941 df-recs 8002 df-rdg 8040 df-er 8283 df-en 8504 df-dom 8505 df-sdom 8506 df-pnf 10671 df-mnf 10672 df-xr 10673 df-ltxr 10674 df-le 10675 df-sub 10866 df-neg 10867 df-nn 11633 df-2 11694 df-n0 11892 df-z 11976 df-uz 12238 df-fz 12887 |
This theorem is referenced by: (None) |
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