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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 13169 | . . 3 ⊢ (1...2) = {1, 2} | |
2 | 1 | raleqi 3323 | . 2 ⊢ (∀𝑥 ∈ (1...2)(𝐹‘𝑥) = if(𝑥 = 1, 𝐴, 𝐵) ↔ ∀𝑥 ∈ {1, 2} (𝐹‘𝑥) = if(𝑥 = 1, 𝐴, 𝐵)) |
3 | 1ex 10829 | . . 3 ⊢ 1 ∈ V | |
4 | 2ex 11907 | . . 3 ⊢ 2 ∈ V | |
5 | fveq2 6717 | . . . 4 ⊢ (𝑥 = 1 → (𝐹‘𝑥) = (𝐹‘1)) | |
6 | iftrue 4445 | . . . 4 ⊢ (𝑥 = 1 → if(𝑥 = 1, 𝐴, 𝐵) = 𝐴) | |
7 | 5, 6 | eqeq12d 2753 | . . 3 ⊢ (𝑥 = 1 → ((𝐹‘𝑥) = if(𝑥 = 1, 𝐴, 𝐵) ↔ (𝐹‘1) = 𝐴)) |
8 | fveq2 6717 | . . . 4 ⊢ (𝑥 = 2 → (𝐹‘𝑥) = (𝐹‘2)) | |
9 | 1ne2 12038 | . . . . . . . 8 ⊢ 1 ≠ 2 | |
10 | 9 | necomi 2995 | . . . . . . 7 ⊢ 2 ≠ 1 |
11 | pm13.181 3024 | . . . . . . 7 ⊢ ((𝑥 = 2 ∧ 2 ≠ 1) → 𝑥 ≠ 1) | |
12 | 10, 11 | mpan2 691 | . . . . . 6 ⊢ (𝑥 = 2 → 𝑥 ≠ 1) |
13 | 12 | neneqd 2945 | . . . . 5 ⊢ (𝑥 = 2 → ¬ 𝑥 = 1) |
14 | 13 | iffalsed 4450 | . . . 4 ⊢ (𝑥 = 2 → if(𝑥 = 1, 𝐴, 𝐵) = 𝐵) |
15 | 8, 14 | eqeq12d 2753 | . . 3 ⊢ (𝑥 = 2 → ((𝐹‘𝑥) = if(𝑥 = 1, 𝐴, 𝐵) ↔ (𝐹‘2) = 𝐵)) |
16 | 3, 4, 7, 15 | ralpr 4616 | . 2 ⊢ (∀𝑥 ∈ {1, 2} (𝐹‘𝑥) = if(𝑥 = 1, 𝐴, 𝐵) ↔ ((𝐹‘1) = 𝐴 ∧ (𝐹‘2) = 𝐵)) |
17 | 2, 16 | bitri 278 | 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 209 ∧ wa 399 = wceq 1543 ≠ wne 2940 ∀wral 3061 ifcif 4439 {cpr 4543 ‘cfv 6380 (class class class)co 7213 1c1 10730 2c2 11885 ...cfz 13095 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1803 ax-4 1817 ax-5 1918 ax-6 1976 ax-7 2016 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2158 ax-12 2175 ax-ext 2708 ax-sep 5192 ax-nul 5199 ax-pow 5258 ax-pr 5322 ax-un 7523 ax-cnex 10785 ax-resscn 10786 ax-1cn 10787 ax-icn 10788 ax-addcl 10789 ax-addrcl 10790 ax-mulcl 10791 ax-mulrcl 10792 ax-mulcom 10793 ax-addass 10794 ax-mulass 10795 ax-distr 10796 ax-i2m1 10797 ax-1ne0 10798 ax-1rid 10799 ax-rnegex 10800 ax-rrecex 10801 ax-cnre 10802 ax-pre-lttri 10803 ax-pre-lttrn 10804 ax-pre-ltadd 10805 ax-pre-mulgt0 10806 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 848 df-3or 1090 df-3an 1091 df-tru 1546 df-fal 1556 df-ex 1788 df-nf 1792 df-sb 2071 df-mo 2539 df-eu 2568 df-clab 2715 df-cleq 2729 df-clel 2816 df-nfc 2886 df-ne 2941 df-nel 3047 df-ral 3066 df-rex 3067 df-reu 3068 df-rab 3070 df-v 3410 df-sbc 3695 df-csb 3812 df-dif 3869 df-un 3871 df-in 3873 df-ss 3883 df-pss 3885 df-nul 4238 df-if 4440 df-pw 4515 df-sn 4542 df-pr 4544 df-tp 4546 df-op 4548 df-uni 4820 df-iun 4906 df-br 5054 df-opab 5116 df-mpt 5136 df-tr 5162 df-id 5455 df-eprel 5460 df-po 5468 df-so 5469 df-fr 5509 df-we 5511 df-xp 5557 df-rel 5558 df-cnv 5559 df-co 5560 df-dm 5561 df-rn 5562 df-res 5563 df-ima 5564 df-pred 6160 df-ord 6216 df-on 6217 df-lim 6218 df-suc 6219 df-iota 6338 df-fun 6382 df-fn 6383 df-f 6384 df-f1 6385 df-fo 6386 df-f1o 6387 df-fv 6388 df-riota 7170 df-ov 7216 df-oprab 7217 df-mpo 7218 df-om 7645 df-1st 7761 df-2nd 7762 df-wrecs 8047 df-recs 8108 df-rdg 8146 df-er 8391 df-en 8627 df-dom 8628 df-sdom 8629 df-pnf 10869 df-mnf 10870 df-xr 10871 df-ltxr 10872 df-le 10873 df-sub 11064 df-neg 11065 df-nn 11831 df-2 11893 df-n0 12091 df-z 12177 df-uz 12439 df-fz 13096 |
This theorem is referenced by: (None) |
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