Maths, Mathematics, Discrete Mathematics, Discrete Maths, Sets.
operation: i.e. A ∩ B = B ∩ A. The intersection of A, B The axiom of extensionality, or axiom of extension First of all, we need to tackle the question "What is an axiom". It's a hypothesis that is taken to be true. In other words, a self-evident rule. So, the axiom says: Given any set A and any