let E be non empty set ; :: thesis: for F being Subset of (E ^omega )
for TS being non empty transition-system of F
for P being RedSequence of ==>.-relation TS st ex x being set ex u being Element of E ^omega st P . 1 = [x,u] holds
for k being Nat st k in dom P holds
dim2 (P . k),E = (P . k) `2

let F be Subset of (E ^omega ); :: thesis: for TS being non empty transition-system of F
for P being RedSequence of ==>.-relation TS st ex x being set ex u being Element of E ^omega st P . 1 = [x,u] holds
for k being Nat st k in dom P holds
dim2 (P . k),E = (P . k) `2

let TS be non empty transition-system of F; :: thesis: for P being RedSequence of ==>.-relation TS st ex x being set ex u being Element of E ^omega st P . 1 = [x,u] holds
for k being Nat st k in dom P holds
dim2 (P . k),E = (P . k) `2

let P be RedSequence of ==>.-relation TS; :: thesis: ( ex x being set ex u being Element of E ^omega st P . 1 = [x,u] implies for k being Nat st k in dom P holds
dim2 (P . k),E = (P . k) `2 )

given x being set , u being Element of E ^omega such that A: P . 1 = [x,u] ; :: thesis: for k being Nat st k in dom P holds
dim2 (P . k),E = (P . k) `2

let k be Nat; :: thesis: ( k in dom P implies dim2 (P . k),E = (P . k) `2 )
assume B: k in dom P ; :: thesis: dim2 (P . k),E = (P . k) `2
per cases ( k > 1 or k <= 1 ) ;
suppose H: k > 1 ; :: thesis: dim2 (P . k),E = (P . k) `2
then consider l being Nat such that
E: k = l + 1 by NAT_1:6;
F: l >= 1 by E, H, NAT_1:19;
G: k <= len P by B, FINSEQ_3:27;
l <= k by E, NAT_1:11;
then l <= len P by G, XXREAL_0:2;
then l in dom P by F, FINSEQ_3:27;
then [(P . l),(P . k)] in ==>.-relation TS by B, E, REWRITE1:def 2;
then C: P . k in rng (==>.-relation TS) by RELAT_1:20;
rng (==>.-relation TS) c= [:the carrier of TS,(E ^omega ):] by RELAT_1:def 19;
then consider x1, y1 being set such that
D: ( x1 in the carrier of TS & y1 in E ^omega & P . k = [x1,y1] ) by C, ZFMISC_1:def 2;
thus dim2 (P . k),E = (P . k) `2 by D, DefDim2; :: thesis: verum
end;
suppose E: k <= 1 ; :: thesis: dim2 (P . k),E = (P . k) `2
k >= 1 by B, FINSEQ_3:27;
then k = 1 by E, XXREAL_0:1;
hence dim2 (P . k),E = (P . k) `2 by A, DefDim2; :: thesis: verum
end;
end;