Venn Diagrams are named after English Logician John Venn

The Venn Diagrams are named  after  English  Logician  John  Venn (1834-1923)  to present  pictorial  representation. The Universal Set, say  U or X is denoted by a region enclosed by a ractangle and one or more sets say, A, B, C are shown through circuits or closed curves within these rectangles. These circuits or closed curves intersect each other if there are any common elements amongst them, If there are no common elements then they are shown separately as disjionts.

Several set relations can be easily shown by these diagrams. These are useful to illustrate the set relations, such as the subset, set relations and the set-operations such as intersection, union, complemention, etc. by using regions in aplane to indicate sets. But Venn Diagrams (also known as Venn Euler Diagrams) can not be used to prove any statements regarding sets, just as geometric figures can not be used to prove geometric theorems. They are more aids for searching appropiate proofs.