In mathematics, a submatrix is a matrix formed by selecting certain rows and columns from a bigger matrix. That is, as an array, it is cut down to those entries constrained by row and column.
For example
Then
is a submatrix of A formed by rows 1,2 and columns 1,3,4. This submatrix can also be denoted by A(3;2) which means that it is formed by deleting row 3 and column 2.
The above two methods are common, but there is no standard way to denote a submatrix.
The corresponding concept in determinant theory is of minor determinant, that is, determinant of a square submatrix.
