Conceptual

Scalar Curvature Gap Estimates and Epsilon-Gap Distance Extremality

A twisted-Dirac index-theory estimate bounding how much an area-nonincreasing map of nonzero degree can raise scalar curvature, with no sign assumption on the target's curvature operator, showing every metric on an even-dimensional closed manifold with nonzero Euler characteristic is epsilon-gap distance extremal for some epsilon>=0, plus a boundary analogue for scalar and mean curvature.