3 papers
math.AG2026
Invisible singularities in complex algebraic geometry
Maurício Corrêa, János Kollár, Stefan Schreieder +1
We construct morphisms between smooth complex projective varieties that have singular fibers, but look topologically smooth. We use this to give negative answers to the following f…
math.AG2026
Homology fiber bundles of varieties, that are not topological fiber bundles
MaurÃcio Corrêa, Maurício Corrêa, János Kollár +1
We construct flat, projective morphisms that are -homology fiber bundles, have a smooth total space, but are not smooth. This disproves one of the conjectures of the sec…
math.AG2025
Severi-Brauer varieties; a geometric treatment
János Kollár
These notes present a geometric treatment of Severi-Brauer varieties, without using any results from the theory of central simple algebras or from Galois cohomology. 2026 version:…