theorem Th31: :: FINSEQ_4:31

for p being FinSequence
for x being object st p just_once_values x holds
for k being Nat st k in dom (p - {x}) holds
( ( k < x .. p implies (p - {x}) . k = p . k ) & ( x .. p <= k implies (p - {x}) . k = p . (k + 1) ) )