collaborators

6 papers

math.NT2026

On semi-stable integral models for Shimura varieties

Jie Yang, Ioannis Zachos, Zhihao Zhao

We construct (potentially) semi-stable integral models for a class of Shimura varieties with maximal parahoric level at an odd prime . The main input is an explicit construction…

math.NT2026

On -adic integral moduli schemes and local models for PEL type D

Jie Yang, Ioannis Zachos, Zhihao Zhao

We construct flat integral moduli schemes of PEL type D and the corresponding flat orthogonal Rapoport--Zink spaces with parahoric level structure over a -adic integer ring. The…

math.NT2025

The basic locus of regular ramified unitary Rapoport-Zink spaces at vertex-stabilizer level

Ioannis Zachos, Zhihao Zhao

We construct the Bruhat-Tits stratification of the reduced basic locus of regular ramified unitary Rapoport-Zink spaces of signature at vertex-stabilizer level. To st…

math.NT2025

The basic locus of unitary splitting Rapoport-Zink spaces with vertex stabilizer level

Ioannis Zachos, Zhihao Zhao

We construct the Bruhat-Tits stratification of the ramified unitary splitting Rapoport-Zink space, with the level being the stabilizer of a vertex lattice. To determine certain loc…

math.NT2025

Semi-stable and splitting models for unitary Shimura varieties over ramified places. II

Ioannis Zachos, Zhihao Zhao

We consider Shimura varieties associated to a unitary group of signature . For these varieties, we construct -adic integral models over odd primes which ramify in…

math.NT2025

On the geometry of splitting models

S. Bijakowski, I. Zachos, Z. Zhao

We consider Shimura varieties associated to a unitary group of signature where is even. For these varieties, by using the spin splitting models from Zachos-Zhao, we c…