Framed flow categories were introduced by Cohen, Jones and Segal as a way of
encoding the flow data associated to a Floer functional. A framed flow category gives
rise to a CW complex with one cell for each object of the category. The idea is that
the Floer invariant should take the form of the
stable homotopy type of the resulting
complex, recovering the Floer cohomology as its singular cohomology. Such a framed
flow category was produced, for example, by Lipshitz and Sarkar from the input of a
knot diagram, resulting in a stable homotopy type generalising Khovanov
cohomology.
We give moves that change a framed flow category without changing the
associated stable homotopy type. These are inspired by moves that can be performed
in the Morse–Smale case without altering the underlying smooth manifold. We posit
that if two framed flow categories represent the same stable homotopy type then a
finite sequence of these moves is sufficient to connect the two categories. This is
directed towards the goal of reducing the study of framed flow categories to a
combinatorial calculus.
We provide examples of calculations performed with these moves (related to the
Khovanov framed flow category), and prove some general results about the
simplification of framed flow categories via these moves.