3 papers
math.AG2026
The opposite of admissibility for local systems on line arrangements
Robert Harris
We study local systems on line arrangements for which no admissibility conditions are satisfied. In doing so we demonstrate the existence of these anti-admissible objects in both t…
math.GT2026
Slope Inequalities for the Geography Problem of Spin Symplectic 4-Manifolds
Shintaro Fushida-Hardy, Robert Harris, B. Doug Park
We construct infinitely many new pairwise nondiffeomorphic smooth structures on infinitely many closed simply connected spin 4-manifolds with positive signature. Our construction b…
math.GT2024
Exotic definite four-manifolds with non-cyclic fundamental group
Robert Harris, Patrick Naylor, B. Doug Park
We construct infinitely many pairwise non-diffeomorphic smooth structures on a definite -manifold with non-cyclic fundamental group .