Metamath Proof Explorer


Theorem swrdnd2

Description: Value of the subword extractor outside its intended domain. (Contributed by Alexander van der Vekens, 24-May-2018)

Ref Expression
Assertion swrdnd2 WWordVABBAWAB0WsubstrAB=

Proof

Step Hyp Ref Expression
1 3orass BAWAB0BAWAB0
2 pm2.24 BA¬BAWWordVABWsubstrAB=
3 swrdval WWordVABWsubstrAB=ifA..^BdomWx0..^BAWx+A
4 3 ad2antrr WWordVABWAB0¬BAWsubstrAB=ifA..^BdomWx0..^BAWx+A
5 wrddm WWordVdomW=0..^W
6 lencl WWordVW0
7 3anass W0ABW0AB
8 ssfzoulel W0ABWAB0A..^B0..^WBA
9 8 imp W0ABWAB0A..^B0..^WBA
10 7 9 sylanbr W0ABWAB0A..^B0..^WBA
11 10 con3dimp W0ABWAB0¬BA¬A..^B0..^W
12 sseq2 domW=0..^WA..^BdomWA..^B0..^W
13 12 notbid domW=0..^W¬A..^BdomW¬A..^B0..^W
14 11 13 imbitrrid domW=0..^WW0ABWAB0¬BA¬A..^BdomW
15 14 exp5j domW=0..^WW0ABWAB0¬BA¬A..^BdomW
16 5 6 15 sylc WWordVABWAB0¬BA¬A..^BdomW
17 16 3impib WWordVABWAB0¬BA¬A..^BdomW
18 17 imp31 WWordVABWAB0¬BA¬A..^BdomW
19 18 iffalsed WWordVABWAB0¬BAifA..^BdomWx0..^BAWx+A=
20 4 19 eqtrd WWordVABWAB0¬BAWsubstrAB=
21 20 ex WWordVABWAB0¬BAWsubstrAB=
22 21 expcom WAB0WWordVAB¬BAWsubstrAB=
23 22 com23 WAB0¬BAWWordVABWsubstrAB=
24 2 23 jaoi BAWAB0¬BAWWordVABWsubstrAB=
25 swrdlend WWordVABBAWsubstrAB=
26 25 com12 BAWWordVABWsubstrAB=
27 24 26 pm2.61d2 BAWAB0WWordVABWsubstrAB=
28 1 27 sylbi BAWAB0WWordVABWsubstrAB=
29 28 com12 WWordVABBAWAB0WsubstrAB=