Venn Diagram Symbols - GCSE Maths - Steps, Examples & Worksheet Venn diagrams were created by mathematician John Venn and are used widely today within computer sciences, problem-solving and set theory. To describe a mathematical set using symbols, we need to know the symbols, and what they represent. Imagine the set of numbers from 1 1 to 10 10. We can write out the whole numbers ( integers) such as