👉 In linear algebra, a submatrix of an n-by-n matrix A is any subset of the form [A], where [ ] denotes the row vector representation of a column vector. Submatrices are particularly important in matrix theory because they can be used to represent and manipulate matrices in a compact way. For example: - The first row of [1 2] represents all elements from the first row of A. - The second row of [1 2] is also a submatrix,
