Theorem ccats1pfxeqbi 41431

Description: A word is a prefix of a word with length greater by 1 than the first word iff the second word is the first word concatenated with the last symbol of the second word. Could replace ccats1swrdeqbi 13498. (Contributed by AV, 10-May-2020.)

Assertion

Ref	Expression
ccats1pfxeqbi	|- ( ( W e. Word V /\ U e. Word V /\ ( # ` U ) = ( ( # ` W ) + 1 ) ) -> ( W = ( U prefix ( # ` W ) ) <-> U = ( W ++ <" ( lastS ` U ) "> ) ) )

Proof of Theorem ccats1pfxeqbi

Step	Hyp	Ref	Expression
1		ccats1pfxeq 41421	. 2 |- ( ( W e. Word V /\ U e. Word V /\ ( # ` U ) = ( ( # ` W ) + 1 ) ) -> ( W = ( U prefix ( # ` W ) ) -> U = ( W ++ <" ( lastS ` U ) "> ) ) )
2		simp1 1061	. . . . 5 |- ( ( W e. Word V /\ U e. Word V /\ ( # ` U ) = ( ( # ` W ) + 1 ) ) -> W e. Word V )
3		lencl 13324	. . . . . . . . 9 |- ( W e. Word V -> ( # ` W ) e. NN0 )
4		nn0p1nn 11332	. . . . . . . . 9 |- ( ( # ` W ) e. NN0 -> ( ( # ` W ) + 1 ) e. NN )
5	3, 4	syl 17	. . . . . . . 8 |- ( W e. Word V -> ( ( # ` W ) + 1 ) e. NN )
6	5	3ad2ant1 1082	. . . . . . 7 |- ( ( W e. Word V /\ U e. Word V /\ ( # ` U ) = ( ( # ` W ) + 1 ) ) -> ( ( # ` W ) + 1 ) e. NN )
7		3simpc 1060	. . . . . . 7 |- ( ( W e. Word V /\ U e. Word V /\ ( # ` U ) = ( ( # ` W ) + 1 ) ) -> ( U e. Word V /\ ( # ` U ) = ( ( # ` W ) + 1 ) ) )
8		lswlgt0cl 13356	. . . . . . 7 |- ( ( ( ( # ` W ) + 1 ) e. NN /\ ( U e. Word V /\ ( # ` U ) = ( ( # ` W ) + 1 ) ) ) -> ( lastS ` U ) e. V )
9	6, 7, 8	syl2anc 693	. . . . . 6 |- ( ( W e. Word V /\ U e. Word V /\ ( # ` U ) = ( ( # ` W ) + 1 ) ) -> ( lastS ` U ) e. V )
10	9	s1cld 13383	. . . . 5 |- ( ( W e. Word V /\ U e. Word V /\ ( # ` U ) = ( ( # ` W ) + 1 ) ) -> <" ( lastS ` U ) "> e. Word V )
11		eqidd 2623	. . . . 5 |- ( ( W e. Word V /\ U e. Word V /\ ( # ` U ) = ( ( # ` W ) + 1 ) ) -> ( # ` W ) = ( # ` W ) )
12		pfxccatid 41430	. . . . . 6 |- ( ( W e. Word V /\ <" ( lastS ` U ) "> e. Word V /\ ( # ` W ) = ( # ` W ) ) -> ( ( W ++ <" ( lastS ` U ) "> ) prefix ( # ` W ) ) = W )
13	12	eqcomd 2628	. . . . 5 |- ( ( W e. Word V /\ <" ( lastS ` U ) "> e. Word V /\ ( # ` W ) = ( # ` W ) ) -> W = ( ( W ++ <" ( lastS ` U ) "> ) prefix ( # ` W ) ) )
14	2, 10, 11, 13	syl3anc 1326	. . . 4 |- ( ( W e. Word V /\ U e. Word V /\ ( # ` U ) = ( ( # ` W ) + 1 ) ) -> W = ( ( W ++ <" ( lastS ` U ) "> ) prefix ( # ` W ) ) )
15		oveq1 6657	. . . . 5 |- ( U = ( W ++ <" ( lastS ` U ) "> ) -> ( U prefix ( # ` W ) ) = ( ( W ++ <" ( lastS ` U ) "> ) prefix ( # ` W ) ) )
16	15	eqcomd 2628	. . . 4 |- ( U = ( W ++ <" ( lastS ` U ) "> ) -> ( ( W ++ <" ( lastS ` U ) "> ) prefix ( # ` W ) ) = ( U prefix ( # ` W ) ) )
17	14, 16	sylan9eq 2676	. . 3 |- ( ( ( W e. Word V /\ U e. Word V /\ ( # ` U ) = ( ( # ` W ) + 1 ) ) /\ U = ( W ++ <" ( lastS ` U ) "> ) ) -> W = ( U prefix ( # ` W ) ) )
18	17	ex 450	. 2 |- ( ( W e. Word V /\ U e. Word V /\ ( # ` U ) = ( ( # ` W ) + 1 ) ) -> ( U = ( W ++ <" ( lastS ` U ) "> ) -> W = ( U prefix ( # ` W ) ) ) )
19	1, 18	impbid 202	1 |- ( ( W e. Word V /\ U e. Word V /\ ( # ` U ) = ( ( # ` W ) + 1 ) ) -> ( W = ( U prefix ( # ` W ) ) <-> U = ( W ++ <" ( lastS ` U ) "> ) ) )

Syntax hints:   -> wi 4   <-> wb 196   /\ wa 384   /\ w3a 1037   = wceq 1483   e. wcel 1990   ` cfv 5888  (class class class)co 6650   1c1 9937   + caddc 9939   NNcn 11020   NN0cn0 11292   #chash 13117  Word cword 13291   lastS clsw 13292   ++ cconcat 13293   <"cs1 13294   prefix cpfx 41381

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-8 1992  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-rep 4771  ax-sep 4781  ax-nul 4789  ax-pow 4843  ax-pr 4906  ax-un 6949  ax-cnex 9992  ax-resscn 9993  ax-1cn 9994  ax-icn 9995  ax-addcl 9996  ax-addrcl 9997  ax-mulcl 9998  ax-mulrcl 9999  ax-mulcom 10000  ax-addass 10001  ax-mulass 10002  ax-distr 10003  ax-i2m1 10004  ax-1ne0 10005  ax-1rid 10006  ax-rnegex 10007  ax-rrecex 10008  ax-cnre 10009  ax-pre-lttri 10010  ax-pre-lttrn 10011  ax-pre-ltadd 10012  ax-pre-mulgt0 10013

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3or 1038  df-3an 1039  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-eu 2474  df-mo 2475  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ne 2795  df-nel 2898  df-ral 2917  df-rex 2918  df-reu 2919  df-rab 2921  df-v 3202  df-sbc 3436  df-csb 3534  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-pss 3590  df-nul 3916  df-if 4087  df-pw 4160  df-sn 4178  df-pr 4180  df-tp 4182  df-op 4184  df-uni 4437  df-int 4476  df-iun 4522  df-br 4654  df-opab 4713  df-mpt 4730  df-tr 4753  df-id 5024  df-eprel 5029  df-po 5035  df-so 5036  df-fr 5073  df-we 5075  df-xp 5120  df-rel 5121  df-cnv 5122  df-co 5123  df-dm 5124  df-rn 5125  df-res 5126  df-ima 5127  df-pred 5680  df-ord 5726  df-on 5727  df-lim 5728  df-suc 5729  df-iota 5851  df-fun 5890  df-fn 5891  df-f 5892  df-f1 5893  df-fo 5894  df-f1o 5895  df-fv 5896  df-riota 6611  df-ov 6653  df-oprab 6654  df-mpt2 6655  df-om 7066  df-1st 7168  df-2nd 7169  df-wrecs 7407  df-recs 7468  df-rdg 7506  df-1o 7560  df-oadd 7564  df-er 7742  df-en 7956  df-dom 7957  df-sdom 7958  df-fin 7959  df-card 8765  df-pnf 10076  df-mnf 10077  df-xr 10078  df-ltxr 10079  df-le 10080  df-sub 10268  df-neg 10269  df-nn 11021  df-n0 11293  df-xnn0 11364  df-z 11378  df-uz 11688  df-fz 12327  df-fzo 12466  df-hash 13118  df-word 13299  df-lsw 13300  df-concat 13301  df-s1 13302  df-substr 13303  df-pfx 41382

This theorem is referenced by:  reuccatpfxs1  41434