33 citations · 91 across the 18 of their papers we have counts for
18 papers
When is Frobenius epic?
Javier Carvajal-Rojas, Rankeya Datta, Noah Olander +1
We prove that a homomorphism of rings of prime characteristic is b-nil formally unramified if and only if its relative Frobenius is an epimorphism. We specialize this result under…
Adjoint test modules along Cohen--Macaulay morphisms
Javier Carvajal-Rojas, Axel Stäbler
We provide a transformation rule for adjoint test modules along Cohen--Macaulay maps between Cohen--Macaulay varieties that have -rational geometric fibers. This is, in part, an…
Pulling back Cartier structures along regular maps
Javier Carvajal-Rojas, Axel Stäbler
We introduce a framework for pulling back Cartier modules and their associated invariants along regular -finite morphisms. To achieve this, we construct a relative Cartier isomo…
On pristine morphisms
Javier Carvajal-Rojas, Axel Stäbler
We investigate flat morphisms of schemes of positive characteristic whose relative Frobenius is an isomorphism, which we call pristine. We show that these give rise to a natural Gr…
The geometry of Frobenius on toric varieties
Javier Carvajal-Rojas, Emre Alp Özavcı
We give a geometric description of the positivity of the Frobenius-trace kernel on a -factorial projective toric variety. To do so, we define its Frobenius support as w…
On tame ramification and centers of -purity
Javier Carvajal-Rojas, Anne Fayolle
We introduce a notion of tame ramification for general finite covers. When specialized to the separable case, it extends to higher dimensions the classical notion of tame ramificat…
Singularities of determinantal pure pairs
Javier Carvajal-Rojas, Arnaud Vilpert
Let be a generic determinantal affine variety over a perfect field of characteristic and be a standard prime divisor generator of $\mathrm{Cl}(X) \cong…
Varieties with ample Frobenius-trace kernel
Javier Carvajal-Rojas, Zsolt Patakfalvi
In the search of a projective analog of Kunz's theorem and a Frobenius-theoretic analog of Mori--Hartshorne's theorem, we investigate the positivity of the kernel of the Frobenius…
On the behavior of stringy motives under Galois quasi-étale covers
Javier Carvajal-Rojas, Takehiko Yasuda
We investigate the behavior of stringy motives under Galois quasi-étale covers. We prove that they descend under such covers in a sense defined via their Poincaré realizations. Fur…
On the local étale fundamental group of KLT threefold singularities
Javier Carvajal-Rojas, Axel Stäbler, János Kollár
Let be KLT threefold singularity over an algebraically closed field of positive characteristic . We prove that its local étale fundamental group is tame and finite. Furthe…
Tame fundamental groups of pure pairs and Abhyankar's lemma
Javier Carvajal-Rojas, Axel Stäbler
Let be a strictly local normal -domain of positive characteristic and be a prime divisor on . We study the Galois category of finite…
Covers of rational double points in mixed characteristic
Javier Carvajal-Rojas, Linquan Ma, Thomas Polstra +2
We further the classification of rational surface singularities. Suppose is a strictly Henselian regular local ring of mixed characteristic $(0, p…
On the behavior of -signatures, splitting primes, and test modules under finite covers
Javier Carvajal-Rojas, Axel Stäbler
We give a comprehensive treatment on how -signatures, splitting primes, splitting ratios, and test modules behave under finite covers. To this end, we expand on the notion of tr…
The Uniform Symbolic Topology Property for Diagonally -regular Algebras
Javier Carvajal-Rojas, Daniel Smolkin
Let be a field of positive characteristic. Building on the work of the second named author, we define a new class of -algebras, called diagonally -regular algebras, for w…
Finite torsors over strongly -regular singularities
Javier Carvajal-Rojas
We investigate finite torsors over big opens of spectra of strongly -regular germs that do not extend to torsors over the whole spectrum. Let be a strongly…
Bertini Theorems for -signature and Hilbert-Kunz multiplicity
Javier Carvajal-Rojas, Karl Schwede, Kevin Tucker
We show that Bertini theorems hold for -signature and Hilbert--Kunz multiplicity. In particular, if is normal and quasi-projective with -signature…
Étale fundamental groups of strongly -regular schemes
Bhargav Bhatt, Javier Carvajal-Rojas, Patrick Graf +2
We prove that a strongly -regular scheme admits a finite, generically Galois, and étale-in-codimension-one cover such that the étale fundamental groups…
Fundamental groups of -regular singularities via -signature
Javier Carvajal-Rojas, Karl Schwede, Kevin Tucker
We prove that the local etale fundamental group of a strongly -regular singularity is finite (and likewise for the étale fundamental group of the complement of a codimension $\g…