theorem Th75: :: FINSEQ_4:75

for x1, x2, x3, x4, x5 being object holds
( <*x1,x2,x3,x4,x5*> = <*x1,x2,x3*> ^ <*x4,x5*> & <*x1,x2,x3,x4,x5*> = <*x1,x2,x3,x4*> ^ <*x5*> & <*x1,x2,x3,x4,x5*> = (((<*x1*> ^ <*x2*>) ^ <*x3*>) ^ <*x4*>) ^ <*x5*> & <*x1,x2,x3,x4,x5*> = <*x1,x2*> ^ <*x3,x4,x5*> & <*x1,x2,x3,x4,x5*> = <*x1*> ^ <*x2,x3,x4,x5*> )