3 papers
math.AG2026
Desmic quartic surfaces in arbitrary characteristic
Igor Dolgachev, Shigeyuki Kondo
A desmic quartic surface is a birational model of the Kummer surface of the self-product of an elliptic curve. We recall the classical geometry of these surfaces and study their an…
math.AG2026
Compactifications of the Eisenstein ancestral Deligne-Mostow variety
Klaus Hulek, Shigeyuki Kondo, Yota Maeda
All arithmetic non-compact ball quotients by Deligne-Mostow's unitary monodromy group arise as sub-ball quotients of either of two spaces called ancestral cases, corresponding to G…
math.AG2025
Bitangent surfaces and involutions of quartic surfaces
Igor Dolgachev, Shigeyuki KondÅ, Shigeyuki Kondō
We study the congruence of bitangent lines of an irreducible surface in the 3-dimensional projective space in arbitrary characteristic, with special attention to quartic surfaces w…