Splitting obstructions and properties of objects in the Nil categories
Tom 161 / 1999
Fundamenta Mathematicae 161 (1999), 155-165
DOI: 10.4064/fm-161-1-2-155-165
Streszczenie
We show that the objects of Bass-Farrell categories which represent 0 in the corresponding Nil groups are precisely those which are stably triangular. This extends to Waldhausen's Nil group of the amalgamated free product with index 2 factors. Applications include a description of Cappell's special UNil group and reformulations of those splitting and fibering theorems which use the Nil groups.
