Ringschluss
In mathematics, a Ringschluss (German: Beweis durch Ringschluss, lit. 'Proof by ring-inference') is a mathematical proof technique where the equivalence of several statements can be proven without having to prove all pairwise equivalences directly. In English it is also sometimes called a cycle of implications, closed chain inference, or circular implication; however, it should be distinguished from circular reasoning, a logical fallacy.