theorem Th63: :: INTPRO_2:62

for x1, x2, x3, x4, x5, x6, x7, x8, x9, x10 being object holds {x1,x2,x3,x4,x5,x6,x7,x8,x9,x10} = {x2,x3,x4,x5,x6,x7,x8,x9,x10} \/ {x1}