IBM 5100 Basic Reference Manual page 129

(
Example
The following example shows the executiC!n of a MAT (identity function) statement:
50 DIM X(t6)
< ,
(
60 MAT X(4,4)
=
IDN
The resulting values are:
(
0
0
0
0 0 0
X is
0 0 0
0 0
0
(
125