Array functions ☆
Let M be an array, i be a numeric expression below.

LBOUND(M,i) | The lower bound of the i-th dimension.
UBOUND(M,i) | The upper bound of the i-th dimension.
SIZE(M,i) | The number of the i-th subscripts.
SIZE(M) | The number of current elements.
MAXSIZE(M) | The upper limit of the number of elements.

Example 1.
`DIM A(8,9)`
yields
lbound(A,1)=1, lbound(a,2)=1, ubound(a,1)=8, ubound(a,2)=9
size(A,1)=8, size(A,2)=9, size(A)=72, maxsize(A)=72
if no OPTION BASE exists.
Example 2.

    10 DIM a(10)
    20 MAT a=ZER(5)

yields SIZE(a)=5，MAXSIZE(a)=10.
if no OPTION BASE exists.
If M is 1-dimensional, the following abbreviations are allowed.

LBOUND(M) | The lower bound of the subscript of M.
UBOUND(M) | The upper bound of the subscript of M.

DET-function
Let M be a 2-dimensional array.
DET(A) The determinant of A
If A is not square, an exception shall be caused on execution.
Original enhancement to Full BASIC
An matrix formula can be wirtten as an argument to the DET function.
See Enhanments in MAT statements
DOT-function
Let A,B be 1-dimensional arrays
DOT(A,B) The dot (inner) product of A and B.
If the size of A and B are different, an exception shall be caused on execution.