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Mirrors > Home > MPE Home > Th. List > wfr2 | Structured version Visualization version GIF version |
Description: The Principle of Well-Founded Recursion, part 2 of 3. Next, we show that the value of 𝐹 at any 𝑋 ∈ 𝐴 is 𝐺 recursively applied to all "previous" values of 𝐹. (Contributed by Scott Fenton, 18-Apr-2011.) (Revised by Mario Carneiro, 26-Jun-2015.) |
Ref | Expression |
---|---|
wfr2.1 | ⊢ 𝑅 We 𝐴 |
wfr2.2 | ⊢ 𝑅 Se 𝐴 |
wfr2.3 | ⊢ 𝐹 = wrecs(𝑅, 𝐴, 𝐺) |
Ref | Expression |
---|---|
wfr2 | ⊢ (𝑋 ∈ 𝐴 → (𝐹‘𝑋) = (𝐺‘(𝐹 ↾ Pred(𝑅, 𝐴, 𝑋)))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | wfr2.1 | . . . 4 ⊢ 𝑅 We 𝐴 | |
2 | wfr2.2 | . . . 4 ⊢ 𝑅 Se 𝐴 | |
3 | wfr2.3 | . . . 4 ⊢ 𝐹 = wrecs(𝑅, 𝐴, 𝐺) | |
4 | eqid 2825 | . . . 4 ⊢ (𝐹 ∪ {〈𝑥, (𝐺‘(𝐹 ↾ Pred(𝑅, 𝐴, 𝑥)))〉}) = (𝐹 ∪ {〈𝑥, (𝐺‘(𝐹 ↾ Pred(𝑅, 𝐴, 𝑥)))〉}) | |
5 | 1, 2, 3, 4 | wfrlem16 7696 | . . 3 ⊢ dom 𝐹 = 𝐴 |
6 | 5 | eleq2i 2898 | . 2 ⊢ (𝑋 ∈ dom 𝐹 ↔ 𝑋 ∈ 𝐴) |
7 | 1, 2, 3 | wfr2a 7698 | . 2 ⊢ (𝑋 ∈ dom 𝐹 → (𝐹‘𝑋) = (𝐺‘(𝐹 ↾ Pred(𝑅, 𝐴, 𝑋)))) |
8 | 6, 7 | sylbir 227 | 1 ⊢ (𝑋 ∈ 𝐴 → (𝐹‘𝑋) = (𝐺‘(𝐹 ↾ Pred(𝑅, 𝐴, 𝑋)))) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 = wceq 1658 ∈ wcel 2166 ∪ cun 3796 {csn 4397 〈cop 4403 Se wse 5299 We wwe 5300 dom cdm 5342 ↾ cres 5344 Predcpred 5919 ‘cfv 6123 wrecscwrecs 7671 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1896 ax-4 1910 ax-5 2011 ax-6 2077 ax-7 2114 ax-8 2168 ax-9 2175 ax-10 2194 ax-11 2209 ax-12 2222 ax-13 2391 ax-ext 2803 ax-rep 4994 ax-sep 5005 ax-nul 5013 ax-pow 5065 ax-pr 5127 ax-un 7209 |
This theorem depends on definitions: df-bi 199 df-an 387 df-or 881 df-3or 1114 df-3an 1115 df-tru 1662 df-ex 1881 df-nf 1885 df-sb 2070 df-mo 2605 df-eu 2640 df-clab 2812 df-cleq 2818 df-clel 2821 df-nfc 2958 df-ne 3000 df-ral 3122 df-rex 3123 df-reu 3124 df-rmo 3125 df-rab 3126 df-v 3416 df-sbc 3663 df-csb 3758 df-dif 3801 df-un 3803 df-in 3805 df-ss 3812 df-nul 4145 df-if 4307 df-sn 4398 df-pr 4400 df-op 4404 df-uni 4659 df-iun 4742 df-br 4874 df-opab 4936 df-mpt 4953 df-id 5250 df-po 5263 df-so 5264 df-fr 5301 df-se 5302 df-we 5303 df-xp 5348 df-rel 5349 df-cnv 5350 df-co 5351 df-dm 5352 df-rn 5353 df-res 5354 df-ima 5355 df-pred 5920 df-iota 6086 df-fun 6125 df-fn 6126 df-f 6127 df-f1 6128 df-fo 6129 df-f1o 6130 df-fv 6131 df-wrecs 7672 |
This theorem is referenced by: wfr3 7701 tfr2ALT 7763 bpolylem 15151 |
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