Framed functions arose in the work of K. Igusa defining cohomology invariants for smooth manifold bundles (Igusa-Klein torsion). In the late 80's, he proved a strong connectivity result about the "space of framed functions" using Morse theory and conjectured that this space was, in fact, contractible. Jacob Lurie recently verified this conjecture using the language of higher category theory in the course of his proof of the Cobordism Hypothesis.
(1) Is there any progress on a more geometric proof of this? The relevant work of Igusa is very geometric and Lurie himself points out that a more direct proof should be found. Perhaps more realistically: is there a geometric heuristic for Lurie's result?
(2) Does anyone know of applications of framed functions beyond defining Igusa-Klein torsion and proving the Cobordism Hypothesis? Pointers into the literature on this topic would be much appreciated.
EDIT: A framed function on $M$ is a pair $(f,\xi)$ of a smooth function $f$ on $M$ having at most $A2$ singularities in the interior of $M$ and no singular points on the boundary, and an orthonormal framing $\xi$ of the negative eigenspace of the Hessian of $f$ at each critical point.
Best Answer
It is possible to prove the contractibility directly (and thereby bypass the obstruction theory arguments sketched at the end of section 3 of my paper). The statement itself is an example of an h-principle: namely, one can show fairly easily that the framed function space of ${\mathbb R}^{n}$ is contractible, so the general result hinges on knowing that the framed function spaces also satisfy some sort of "local to global" principle for arbitrary manifolds. (If I remember correctly, Igusa told me that he and Eliashberg sketched out a proof along these lines, but never had the motivation to write it up.)