Joseph Helfer

collaborators

3 papers

math.CT2026

Set-theoretic universes and paradoxes in 2-topoi

Joseph Helfer

This paper continues the development of (elementary) 2-topos theory, a foundational theory based on an axiomatization of the 2-category of categories. We prove that any 2-topos con…

math.LO2025

Y is a least fixed point combinator

Joseph Helfer

The theory of recursive functions is related in a well-known way to the notion of *least fixed points*, by endowing a set of partial functions with an ordering in terms of their do…

math.AG2025

The integral chow ring of $M_{2}^{c t}$

Joseph Helfer, Eric Jovinelly, Eric Larson +2

This paper computes the integral Chow ring of the moduli space $M_{2}^{c t}$ of stable genus 2 curves of compact type. This is done by excising boundary strata from $M ˉ_{2}$ one-by-…

Set-theoretic universes and paradoxes in 2-topoi

Y is a least fixed point combinator

The integral chow ring of M2ct​

The integral chow ring of $M_{2}^{c t}$