In mathematics, submodular functions are set functions which usually appear in approximation algorithms, functions modeling user preferences in game theory,economics, combinatorial optimization, electrical networks and operations research.
In mathematics, a submodular set function (also known as a submodular function) is a set function whose value, informally, has the property that the difference in the value of the function that a single element makes when added to an input set decreases as the size of the input set increases. These functions have a natural diminishing returns property which makes them suitable for many applications. The marginal gain from adding an element to a set A is at least as high as the marginal gain from adding the same element to a superset of A. Ex:V might be colors of paint in a paint manufacturer: green, red, blue, yellow, white, etc. Producing green when you are already producing yellow and blue is probably cheaper than if you were only producing some other colors.