theorem Th21: :: DESCIP_1:21
for S being non empty set
for x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15, x16 being Element of S ex s being FinSequence of S st
( s is 16 -element & s . 1 = x1 & s . 2 = x2 & s . 3 = x3 & s . 4 = x4 & s . 5 = x5 & s . 6 = x6 & s . 7 = x7 & s . 8 = x8 & s . 9 = x9 & s . 10 = x10 & s . 11 = x11 & s . 12 = x12 & s . 13 = x13 & s . 14 = x14 & s . 15 = x15 & s . 16 = x16 )