To get boolean expression in the product of sum from, from a given Karnaugh map
To get Boolean expression in the product of sum from, from a given karnaugh map one should cover all the 0's present and complement the resulting expression.
A sum-of-products Boolean expression is literally a set of Boolean terms added together, each term being a multiplicative (product) combination of Boolean variables.
Sum of product form is a form of expression in Boolean algebra in which different product terms of inputs are being summed together.
A karnaugh map provides a pictorial method of grouping together expressions with common factors and therefore eliminating unwanted variables. The karnaugh map can also be described as a special arrangement of a truth table.