Affine semigroups having a unique Betti element
  We characterize affine semigroups having one Betti element and we compute some relevant non-unique factorization invariants for these semigroups. As an example, we particularize our description to numerical semigroups. 
Pedro A. Garc\'ia-S\'anchez, Ignacio Ojeda, Jos\'e Carlos Rosales
math.AC math.GR