let x, y be object ; :: thesis: for E being non empty set
for v, w being Element of E ^omega
for F being Subset of (E ^omega)
for TS being non empty transition-system over F
for P being RedSequence of ==>.-relation TS st P . 1 = [x,v] & P . (len P) = [y,w] holds
len v >= len w

let E be non empty set ; :: thesis: for v, w being Element of E ^omega
for F being Subset of (E ^omega)
for TS being non empty transition-system over F
for P being RedSequence of ==>.-relation TS st P . 1 = [x,v] & P . (len P) = [y,w] holds
len v >= len w

let v, w be Element of E ^omega ; :: thesis: for F being Subset of (E ^omega)
for TS being non empty transition-system over F
for P being RedSequence of ==>.-relation TS st P . 1 = [x,v] & P . (len P) = [y,w] holds
len v >= len w

let F be Subset of (E ^omega); :: thesis: for TS being non empty transition-system over F
for P being RedSequence of ==>.-relation TS st P . 1 = [x,v] & P . (len P) = [y,w] holds
len v >= len w

let TS be non empty transition-system over F; :: thesis: for P being RedSequence of ==>.-relation TS st P . 1 = [x,v] & P . (len P) = [y,w] holds
len v >= len w

let P be RedSequence of ==>.-relation TS; :: thesis: ( P . 1 = [x,v] & P . (len P) = [y,w] implies len v >= len w )
assume ( P . 1 = [x,v] & P . (len P) = [y,w] ) ; :: thesis: len v >= len w
then ex u being Element of E ^omega st v = u ^ w by Th53;
hence len v >= len w by Th9; :: thesis: verum