Curry–Howard isomorphism

The Curry-Howard Isomorphism is a connection between two areas of mathematics. It connects logic and type theory. Logic and type theory are both ways of telling us what is true and what is not. In logic, we use things called propositions to tell us if something is true or false. A proposition is like a statement, like "2+2=4" or "It is raining". In type theory, we use things called types to tell us if something is true or false. A type is like a group of similar things, like "red apples" or "chairs". The Curry-Howard Isomorphism says that these two different systems are actually the same thing. They both use logic and mathematics to tell us what is true and what is not. This means that if we can figure out what is true in one of these systems, we can also figure out what is true in the other one!