Numerical semigroups from rational matrices III: semigroups of matricial dimension two and a counterexample to the lonely element conjecture
Arsh Chhabra, Stephan Ramon Garcia · Communications in Algebra · 2025
We characterize additive semigroups in {0,1,2,…} of matricial dimension 2 and produce a counterexample to the conjecture that a numerical semigroup whose small elements are lonely has matricial dimension at most 2.