title: The adjunction problem over torsion-free groups.
abstract: We prove injectivity and relative asphericity for "layered" systems of equations over torsion-free groups, when the exponent matrix is invertible over Z.
authors.affiliation: Mathematics Department, University of Oklahoma, Norman, OK 73019, USA.
authors.forename: Max
authors.initials: M
authors.lastname: Forester
authors.forename: Colin
authors.initials: C
authors.lastname: Rourke