3 citations · 6 across the 9 of their papers we have counts for
9 papers · 1 filter
Local indicability in the presence of diagrammatic reducibility
Jens Harlander, Stephan Rosebrock
If a complex is a subcomplex of a diagrammatically reducible 2-complex that has locally indicable fundamental group, then has locally indicable fundamental group. This…
Relative Non-Positive Immersion
Jens Harlander, Stephan Rosebrock
A 2-complex has collapsing non-positive immersion if for every combinatorial immersion , where is finite, connected and does not allow collapses, either …
The Local Structure of Injective LOT-Complexes
Jens Harlander, Stephan Rosebrock
Labeled oriented trees, LOT's, encode spines of ribbon discs in the 4-ball and ribbon 2-knots in the 4-sphere. The unresolved asphericity question for these spines is a major test…
Ribbon 2-knot groups of Coxeter type
Jens Harlander, Stephan Rosebrock
Wirtinger presentations of deficiency 1 appear in the context of knots, long virtual knots, and ribbon 2-knots. They are encoded by (word) labeled oriented trees and, for that reas…
Relative Vertex Asphericity
Jens Harlander, Stephan Rosebrock
Diagrammatic reducibility DR and its generalization vertex asphericity VA are combinatorial tools developed for detecting asphericity of a 2-complex. Here we present tests for a re…
Relative Combinatorial Asphericity
Stephan Rosebrock, Jens Harlander
Relative notions of combinatorial asphericity have been used to prove that injective labeled oriented trees (which encode spines of ribbon 2-knots) are aspherical. This article pre…
Directed diagrammatic reducibility
Jens Harlander, Stephan Rosebrock
We introduce the notion of directed diagrammatic reducibility which is a relative version of diagrammatic reducibility. Directed diagrammatic reducibility has strong group theoreti…
Aspherical Word Labeled Oriented Graphs and Cyclically Presented Groups
Jens Harlander, Stephan Rosebrock
A {\em word labeled oriented graph} (WLOG) is an oriented graph on vertices , where each oriented edge is labeled by a word in . WLOGs gi…
Injective Labeled Oriented Trees are Aspherical
Jens Harlander, Stephan Rosebrock
A labeled oriented tree is called injective if each generator occurs at most once as an edge label. We show that injective labeled oriented trees are aspherical. The proof relies o…