If a doubly nested list of matrices is given, then ring elements can be used for 1 by 1 blocks, and 0 represents a zero block.
This is essentially the same as matrix(List) together with the specification of the ring.
i1 : R = QQ[a..d]; |
i2 : f = matrix{{a,b},{c,0}} o2 = | a b | | c 0 | 2 2 o2 : Matrix R <--- R |
i3 : h = matrix{{f,f},{f,0}} o3 = | a b a b | | c 0 c 0 | | a b 0 0 | | c 0 0 0 | 4 4 o3 : Matrix R <--- R |