Hp50 Real Matrix does not allow subst aij real by a'ij complex

[Gil]

"If you are going to want to insert complex numbers into an array, you should start out with a complex array. You can turn a real array into a complex array with imaginary parts = 0 by
DUP SIZE 0 CON R\->C."

Easier
Real Matrix × (1, 0).

How would you call such a Matrix
with complex and real numbers and no apparent algebraic expression
[[ (5.,6.) (5.,6.) ]
[ (7.,9.) 3 ]] ?