  The existence of trace links between artifacts of the software development
life cycle can improve the efficiency of many activities during software
development, maintenance and operations. Unfortunately, the creation and
maintenance of trace links is time-consuming and error-prone. Research efforts
have been spent to automatically compute trace links and lately gained
momentum, e.g., due to the availability of powerful tools in the area of
natural language processing. In this paper, we report on some observations that
we made during studying non-linear similarity measures for computing trace
links. We argue, that taking a geometric viewpoint on semantic similarity can
be helpful for future traceability research. We evaluated our observations on a
dataset of four open source projects and two industrial projects. We
furthermore point out that our findings are more general and can build the
basis for other information retrieval problems as well.
