A growing number of largely uncoordinated initiatives focus on research software sustainability. A comprehensive mapping of the research software sustainability space can help identify gaps in their efforts, track results, and avoid duplication of work. To this end, this paper suggests enhancing an existing schematic of activities in research software sustainability, and formalizing it in a directed graph model. Such a model can be further used to define a classification schema which, applied to research results in the field, can drive the identification of past activities and the planning of future efforts.

5 pages, 3 figures, 1 table, accepted as a long paper for the 9th International Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE6.1), co-locating with IEEE eScience 2018