2019/02/14 by Facchini, Alberto, Zadeh, Leila Heidari
#18A99 #20M20 #FOS: Mathematics #Group Theory (math.GR)
paper · doi:10.48550/arxiv.1902.05507
Several elementary properties of the symmetric group Sn extend in a nice way to the full transformation monoid Mn of all maps of the set X:=\1,2,3,…,n\ into itself. The group Sn turns out to be in some sense the torsion part of the monoid Mn. More precisely, there is a pretorsion theory in the category of all maps f\colon X→ X, X an arbitrary finite non-empty set, in which bijections are exactly the torsion objects.