let D be non empty set ; :: thesis: for a1, a2 being Element of D holds <*<*a1,a2*>*> is Matrix of 1,2,D
let a1, a2 be Element of D; :: thesis: <*<*a1,a2*>*> is Matrix of 1,2,D
A1: <*a1,a2*> is FinSequence of D by FINSEQ_2:15;
len <*a1,a2*> = 2 by FINSEQ_1:61;
hence <*<*a1,a2*>*> is Matrix of 1,2,D by A1, Th11; :: thesis: verum