Publications > Artigos em Revistas Internacionais

Majors of functions

Couceiro, Miguel; Lehtonen, Erkko

Order, 35 (2018), 233–246
http://dx.doi.org/10.1007/s11083-017-9428-1

We investigate the minor order of functions, focusing on upper covers and common upper bounds of pairs of functions. We show that two functions of arities m and n have a common upper bound if and only if they have a common lower bound, and if a common upper bound exists, then there is one of arity m + n ? 1. Moreover, we determine the possible essential arities of upper covers of functions.