## 3x+1

In algebra, the 3x + 1 semigroup is a special subsemigroup of the multiplicative semigroup of all positive rational numbers. The elements of a generating set of this semigroup are related to the sequence of numbers involved in the still open Collatz conjecture or the “3x + 1 problem”. The 3x + 1 semigroup has been used to prove a weaker form of the Collatz conjecture. In fact, it […]