As given in the Introduction to Matrix, Vector and Tensor Algebra, Matrices are Tensors having Elements organised across a Table of Rows and Columns.
A Matrix having \(M\) Rows and \(N\) Columns is called an \(M \times N\) Matrix. The Number of Rows and Columns in a Matrix give the Dimensions of the Matrix. Each element of any Matrix is called a Matrix Component.
A Matrix having Equal number of Rows and Columns (i.e \(M=N\)) is called a Square Matrix. A \(M \times M\) Square Matrix is also called a Matrix of Order \(M\).
A Matrix having only a Single Column and Multiple Rows (i.e \(M \times 1\)) is called a Column Matrix or a Vector.
A Matrix having only a Single Row and Multiple Columns (i.e \(1 \times N\)) is called a Row Matrix or a Co-Vector.
A Matrix having More than 1 Row and More than 1 Column can be said to contain a Set of Vectors where each column of the Matrix represents a Vector.
Given a \(M \times N\) Matrix \(A\), the element at it's \(i^{th}\) Row and \(j^{th}\) Column is denoted as \(a_{ij}\).
For any \(M \times N\) Matrix \(A\) (where \(M>1\) and \(N>1\)), the Diagonal Elements from Top Left to Bottom Row or Right Most Column (or both) form the Main Diagonal of the Matrix. The elements \(a_{ij}\) where \(i=j\) are called the Main Diagonal Elements.
Any Matrix containing only Real Numbers/Variables/Functions as it's Components is called a Real Matrix. Any Matrix containing Atleast One Complex or Imaginary Number/Variable/Function as it's Components is called a Complex Matrix.
The following examples demonstrate how different Matrix Types explained above are represented