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Theorem revs1 14748

Description: Singleton words are their own reverses. (Contributed by Stefan O'Rear, 26-Aug-2015.) (Revised by Mario Carneiro, 26-Feb-2016.)

**Assertion**
Ref	Expression
revs1	⊢ (reverse‘⟨“𝑆”⟩) = ⟨“𝑆”⟩

**Proof of Theorem revs1**
Step	Hyp	Ref	Expression
1		s1cli 14588	. . . . 5 ⊢ ⟨“𝑆”⟩ ∈ Word V
2		s1len 14589	. . . . . . 7 ⊢ (♯‘⟨“𝑆”⟩) = 1
3		1nn 12254	. . . . . . 7 ⊢ 1 ∈ ℕ
4	2, 3	eqeltri 2825	. . . . . 6 ⊢ (♯‘⟨“𝑆”⟩) ∈ ℕ
5		lbfzo0 13705	. . . . . 6 ⊢ (0 ∈ (0..^(♯‘⟨“𝑆”⟩)) ↔ (♯‘⟨“𝑆”⟩) ∈ ℕ)
6	4, 5	mpbir 230	. . . . 5 ⊢ 0 ∈ (0..^(♯‘⟨“𝑆”⟩))
7		revfv 14746	. . . . 5 ⊢ ((⟨“𝑆”⟩ ∈ Word V ∧ 0 ∈ (0..^(♯‘⟨“𝑆”⟩))) → ((reverse‘⟨“𝑆”⟩)‘0) = (⟨“𝑆”⟩‘(((♯‘⟨“𝑆”⟩) − 1) − 0)))
8	1, 6, 7	mp2an 691	. . . 4 ⊢ ((reverse‘⟨“𝑆”⟩)‘0) = (⟨“𝑆”⟩‘(((♯‘⟨“𝑆”⟩) − 1) − 0))
9	2	oveq1i 7430	. . . . . . . . 9 ⊢ ((♯‘⟨“𝑆”⟩) − 1) = (1 − 1)
10		1m1e0 12315	. . . . . . . . 9 ⊢ (1 − 1) = 0
11	9, 10	eqtri 2756	. . . . . . . 8 ⊢ ((♯‘⟨“𝑆”⟩) − 1) = 0
12	11	oveq1i 7430	. . . . . . 7 ⊢ (((♯‘⟨“𝑆”⟩) − 1) − 0) = (0 − 0)
13		0m0e0 12363	. . . . . . 7 ⊢ (0 − 0) = 0
14	12, 13	eqtri 2756	. . . . . 6 ⊢ (((♯‘⟨“𝑆”⟩) − 1) − 0) = 0
15	14	fveq2i 6900	. . . . 5 ⊢ (⟨“𝑆”⟩‘(((♯‘⟨“𝑆”⟩) − 1) − 0)) = (⟨“𝑆”⟩‘0)
16		ids1 14580	. . . . . . 7 ⊢ ⟨“𝑆”⟩ = ⟨“( I ‘𝑆)”⟩
17	16	fveq1i 6898	. . . . . 6 ⊢ (⟨“𝑆”⟩‘0) = (⟨“( I ‘𝑆)”⟩‘0)
18		fvex 6910	. . . . . . 7 ⊢ ( I ‘𝑆) ∈ V
19		s1fv 14593	. . . . . . 7 ⊢ (( I ‘𝑆) ∈ V → (⟨“( I ‘𝑆)”⟩‘0) = ( I ‘𝑆))
20	18, 19	ax-mp 5	. . . . . 6 ⊢ (⟨“( I ‘𝑆)”⟩‘0) = ( I ‘𝑆)
21	17, 20	eqtri 2756	. . . . 5 ⊢ (⟨“𝑆”⟩‘0) = ( I ‘𝑆)
22	15, 21	eqtri 2756	. . . 4 ⊢ (⟨“𝑆”⟩‘(((♯‘⟨“𝑆”⟩) − 1) − 0)) = ( I ‘𝑆)
23	8, 22	eqtri 2756	. . 3 ⊢ ((reverse‘⟨“𝑆”⟩)‘0) = ( I ‘𝑆)
24		s1eq 14583	. . 3 ⊢ (((reverse‘⟨“𝑆”⟩)‘0) = ( I ‘𝑆) → ⟨“((reverse‘⟨“𝑆”⟩)‘0)”⟩ = ⟨“( I ‘𝑆)”⟩)
25	23, 24	ax-mp 5	. 2 ⊢ ⟨“((reverse‘⟨“𝑆”⟩)‘0)”⟩ = ⟨“( I ‘𝑆)”⟩
26		revcl 14744	. . . 4 ⊢ (⟨“𝑆”⟩ ∈ Word V → (reverse‘⟨“𝑆”⟩) ∈ Word V)
27	1, 26	ax-mp 5	. . 3 ⊢ (reverse‘⟨“𝑆”⟩) ∈ Word V
28		revlen 14745	. . . . 5 ⊢ (⟨“𝑆”⟩ ∈ Word V → (♯‘(reverse‘⟨“𝑆”⟩)) = (♯‘⟨“𝑆”⟩))
29	1, 28	ax-mp 5	. . . 4 ⊢ (♯‘(reverse‘⟨“𝑆”⟩)) = (♯‘⟨“𝑆”⟩)
30	29, 2	eqtri 2756	. . 3 ⊢ (♯‘(reverse‘⟨“𝑆”⟩)) = 1
31		eqs1 14595	. . 3 ⊢ (((reverse‘⟨“𝑆”⟩) ∈ Word V ∧ (♯‘(reverse‘⟨“𝑆”⟩)) = 1) → (reverse‘⟨“𝑆”⟩) = ⟨“((reverse‘⟨“𝑆”⟩)‘0)”⟩)
32	27, 30, 31	mp2an 691	. 2 ⊢ (reverse‘⟨“𝑆”⟩) = ⟨“((reverse‘⟨“𝑆”⟩)‘0)”⟩
33	25, 32, 16	3eqtr4i 2766	1 ⊢ (reverse‘⟨“𝑆”⟩) = ⟨“𝑆”⟩

Colors of variables: wff setvar class

Syntax hints: = wceq 1534 ∈ wcel 2099 Vcvv 3471 I cid 5575 ‘cfv 6548 (class class class)co 7420 0cc0 11139 1c1 11140 − cmin 11475 ℕcn 12243 ..^cfzo 13660 ♯chash 14322 Word cword 14497 ⟨“cs1 14578 reversecreverse 14741

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1790 ax-4 1804 ax-5 1906 ax-6 1964 ax-7 2004 ax-8 2101 ax-9 2109 ax-10 2130 ax-11 2147 ax-12 2167 ax-ext 2699 ax-rep 5285 ax-sep 5299 ax-nul 5306 ax-pow 5365 ax-pr 5429 ax-un 7740 ax-cnex 11195 ax-resscn 11196 ax-1cn 11197 ax-icn 11198 ax-addcl 11199 ax-addrcl 11200 ax-mulcl 11201 ax-mulrcl 11202 ax-mulcom 11203 ax-addass 11204 ax-mulass 11205 ax-distr 11206 ax-i2m1 11207 ax-1ne0 11208 ax-1rid 11209 ax-rnegex 11210 ax-rrecex 11211 ax-cnre 11212 ax-pre-lttri 11213 ax-pre-lttrn 11214 ax-pre-ltadd 11215 ax-pre-mulgt0 11216

This theorem depends on definitions: df-bi 206 df-an 396 df-or 847 df-3or 1086 df-3an 1087 df-tru 1537 df-fal 1547 df-ex 1775 df-nf 1779 df-sb 2061 df-mo 2530 df-eu 2559 df-clab 2706 df-cleq 2720 df-clel 2806 df-nfc 2881 df-ne 2938 df-nel 3044 df-ral 3059 df-rex 3068 df-reu 3374 df-rab 3430 df-v 3473 df-sbc 3777 df-csb 3893 df-dif 3950 df-un 3952 df-in 3954 df-ss 3964 df-pss 3966 df-nul 4324 df-if 4530 df-pw 4605 df-sn 4630 df-pr 4632 df-op 4636 df-uni 4909 df-int 4950 df-iun 4998 df-br 5149 df-opab 5211 df-mpt 5232 df-tr 5266 df-id 5576 df-eprel 5582 df-po 5590 df-so 5591 df-fr 5633 df-we 5635 df-xp 5684 df-rel 5685 df-cnv 5686 df-co 5687 df-dm 5688 df-rn 5689 df-res 5690 df-ima 5691 df-pred 6305 df-ord 6372 df-on 6373 df-lim 6374 df-suc 6375 df-iota 6500 df-fun 6550 df-fn 6551 df-f 6552 df-f1 6553 df-fo 6554 df-f1o 6555 df-fv 6556 df-riota 7376 df-ov 7423 df-oprab 7424 df-mpo 7425 df-om 7871 df-1st 7993 df-2nd 7994 df-frecs 8287 df-wrecs 8318 df-recs 8392 df-rdg 8431 df-1o 8487 df-er 8725 df-en 8965 df-dom 8966 df-sdom 8967 df-fin 8968 df-card 9963 df-pnf 11281 df-mnf 11282 df-xr 11283 df-ltxr 11284 df-le 11285 df-sub 11477 df-neg 11478 df-nn 12244 df-n0 12504 df-z 12590 df-uz 12854 df-fz 13518 df-fzo 13661 df-hash 14323 df-word 14498 df-s1 14579 df-reverse 14742

This theorem is referenced by: gsumwrev 19320 efginvrel2 19682 vrgpinv 19724

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