Contents:

# Definitions

* Matrix
* Square matrix
* Diagonal matrix
* Row matrix
* Column matrix
* Matrices of the same kind
* The tranpose of a matrix
* 0-matrix
* An identity matrix I
* A scalar matrix S
* The opposite matrix of a matrix
* A symmetric matrix
* A skew-symmetric matrix

# The sum of matrices of the same kind

* Sum of matrices
* Sum properties

# Scalar multiplication

* Definition
* Properties

# Sums in math
# Multiplication of a row matrix by a column matrix
# Multiplication of two matrices A.B
# Properties of multiplication of matrices

* Associativity
* Distributivity
* Theorem 1
* Theorem 2
* Theorem 3
* Theorem 4
* Theorem 5