Free sub-bands of finitely presented bands
JOSEPH LAU · Glasgow Mathematical Journal · 1999
For each variety of bands [Vscr ], we give a formula for ϕ[Vscr ](m,k), which is the largest integer such that for every band B in [Vscr ] generated by m generators and k relations, there is a subset of the generators of size ϕ[Vscr ](m,k) which generates a (relatively) free sub-band of B as a basis. We also determine the semilattice structure of a finitely presented band.