activity
20142026
most citedA co-analytic Cohen indestructible maximal cofinitary group

11 citations · 73 across the 28 of their papers we have counts for

collaborators

28 papers

math.LO2026

Loeb Equivalence for General Internal Probability Spaces

Haosui Duanmu, Xinyu Liu, David Schrittesser

Loeb measure theory stands as one of the most influential concepts in nonstandard analysis, underpinning nearly all applications in probability, stochastic processes, and mathemati…

math.FA2026

Generalized almost disjoint families and injective Banach spaces

Chris Lambie-Hanson, David Schrittesser

A fundamental open problem in the homological theory of Banach spaces is the calculation of the injective dimension of the Banach space . We make a contribution to the study o…

math.LO2025

The happy coexistence of mad families and Laver measurability

Asger Tornquist, David Schrittesser

Let denote a Laver real over . We prove that in there is a infinite mad family. Since and sets are Laver measurable in , this shows that…

math.LO2024

Maximal eventually different families for uniformly weak Ramsey ideals

Jialiang He, Jintao Luo, David Schrittesser +1

We study -maximal eventually different families of functions from the set of natural numbers into itself where is an arbitrary ideal on the set of natural…

math.PR2023

de Finetti's theorem and the existence of regular conditional distributions and strong laws on exchangeable algebras

Peter Potaptchik, Daniel M. Roy, David Schrittesser

We show the following generalizations of the de Finetti--Hewitt--Savage theorem: Given an exchangeable sequence of random elements, the sequence is conditionally i.i.d. if and only…

math.LO2023

Cofinitary groups and projective well-orders

Vera Fischer, Lukas Schembecker, David Schrittesser

We introduce the notion of a tight cofinitary group, which captures forcing indestructibility of maximal cofinitary groups for a long list of partial orders, including Cohen, Sacks…

math.ST2022

Statistical minimax theorems via nonstandard analysis

Haosui Duanmu, Daniel M. Roy, David Schrittesser

For statistical decision problems with finite parameter space, it is well-known that the upper value (minimax value) agrees with the lower value (maximin value). Only under a gener…

math.LO2022★ 2 cited

Coding over Core Models

Sy David Friedman, Ralf Schindler, David Schrittesser

Early in their careers, both Peter Koepke and Philip Welch made major contributions to two important areas of set theory, core model theory and coding, respectively. In this articl…

math.LO2022

Lightface -indescribable cardinals

David Schrittesser

-absoluteness for ccc forcing means that for any ccc forcing , . " inaccessible to reals" means that for any real , ${ω_1}…

math.ST2021

Admissibility is Bayes optimality with infinitesimals

Haosui Duanmu, Daniel M. Roy, David Schrittesser

We give an exact characterization of admissibility in statistical decision problems in terms of Bayes optimality in a so-called nonstandard extension of the original decision probl…

math.FA2021

Loeb Extension and Loeb Equivalence II

Duanmu Haosui, David Schrittesser, William Weiss

The paper answers two open questions that were raised in by Keisler and Sun. The first question asks, if we have two Loeb equivalent spaces and $(Ω, \mathcal G…

math.LO2021★ 5 cited

Constructing maximal cofinitary groups

David Schrittesser

Improving and clarifying a construction of Horowitz and Shelah, we show how to construct (in , that is, without using the Axiom of Choice) maximal cofinitary groups. A…

math.LO2020

Maximal discrete sets

David Schrittesser

We survey results regarding the definability and size of maximal discrete sets in analytic hypergraphs. Our main examples include maximal almost disjoint (or mad) families, $\mathc…

math.LO2020

Loeb Extension and Loeb Equivalence

Robert M. Anderson, Haosui Duanmu, David Schrittesser +1

In Keisler and Sun (2004), the authors raise several open problems on Loeb equivalences between various internal probability spaces. We provide counter-examples for the first two o…

math.LO2020★ 1 cited

The Ramsey property and higher dimensional mad families

David Schrittesser, Asger Törnquist

We prove that under a principle of Ramsey regularity there are no infinite maximal almost disjoint families with respect to the transfinitely iterated Fréchet ideals. The results o…

math.LO2019★ 2 cited

Definable MAD families and forcing axioms

Vera Fischer, David Schrittesser, Thilo Weinert

We show that under the Bounded Proper Forcing Axiom and an anti-large cardinal assumption, there is a MAD family.

math.LO2019★ 4 cited

Minimal definable graphs of definable chromatic number at least three

Raphael Carroy, Benjamin D. Miller, David Schrittesser +1

We show that there is a Borel graph on a standard Borel space of Borel chromatic number three that admits a Borel homomorphism to every analytic graph on a standard Borel space of…

math.LO2019

The Ramsey property implies no mad families

David Schrittesser, Asger Törnquist

We show that if all collections of infinite subsets of have the Ramsey property, then there are no infinite maximal almost disjoint (mad) families. This solves a long-standing…

math.LO2019★ 1 cited

Good projective witnesses

Vera Fischer, Sy David Friedman, David Schrittesser +1

We develop a new forcing notion for adjoining self-coding cofinitary permutations and use it to show that consistently, the minimal cardinality of a maxima…

math.LO2018★ 6 cited

A Sacks indestructible co-analytic maximal eventually different family

Vera Fischer, David Schrittesser

In the constructible universe, we construct a co-analytic maximal family of pairwise eventually different functions from to which remains maximal after ad…

math.LO2018★ 5 cited

Lebesgue's Density Theorem and definable selectors for ideals

Sandra Müller, Philipp Schlicht, David Schrittesser +1

We introduce a notion of density point and prove results analogous to Lebesgue's density theorem for various well-known ideals on Cantor space and Baire space. In fact, we isolate…

math.LO2018★ 6 cited

Maximal almost disjoint families, determinacy, and forcing

Karen Bakke Haga, David Schrittesser, Asger Törnquist

We study the notion of -MAD families where is a Borel ideal on . We show that if is an arbitrary ideal, or is any finite or countably…

math.LO2017★ 9 cited

Compactness of maximal eventually different families

David Schrittesser

We show that there is an effectively closed maximal eventually different family of functions in spaces of the form for $F\colon \mathbb{N} \to \mathbb{N}\cup\{\mathb…

math.LO2017★ 5 cited

On Horowitz and Shelah's Borel maximal eventually different family

David Schrittesser

We show there is a closed (in fact effectively closed, i.e., ) eventually different family (working in ZF or less).