The Karnaugh map (also known as a Veitch diagram) was invented in 1953 by Maurice Karnaugh, a telecommunications engineer at Bell Labs. It is a graphical way of minimizing Boolean expressions. An expression’s truth table is drawn as a matrix in such a way that each row and each column of the matrix puts minterms that differ in the value of a single variable adjacent to each other. Then, by grouping adjacent cells of the matrix, you can identify product terms that eliminate all complemented literals, resulting in a minimized version of the expression.
In a Karnaugh map with n variables, a Boolean term mentioning k of them will have a corresponding rectangle of area 2 n − k . Common sized maps are of 2 variables which is a 2x2 map; 3 variables which is a 2x4 map; and 4 variables which is a 4x4 map
For problems involving more than six variables, solving the Boolean expressions is more preferred than the Karnaugh map.