Publications

Journal and conference papers, and contributions to the mathlib4 library.

Published

2026

  1. WIP: Using Career Panels to Spark Curiosity and Career Awareness Among Mathematics Majors
    Ann W. Clifton and Blake Farman
    In ASEE Annual Conference & Exposition, Jun 2026

2025

  1. Fostering Growth Mindsets: Implementing Standards-Based Grading in College Algebra
    Blake Farman, Ann W. Clifton, William C. Long, and 1 more author
    In ASEE Annual Conference & Exposition, Jun 2025
  2. Work in Progress: First-Year Engineering Students’ Confidence in Communicating Mathematical Content
    Ann W. Clifton, Mary Fendley, Blake Farman, and 1 more author
    In ASEE Annual Conference & Exposition, Jun 2025

2021

  1. Kernels for noncommutative projective schemes
    Matthew Ballard and Blake Farman
    J. Noncommut. Geom., Nov 2021

Formalization: merged into mathlib4

  1. feat(CategoryTheory/Abelian/Preradical): introduce and characterize radicals
    Blake Farman
    Mar 2026
    Following Stenström, a preradical ‘Φ‘ is called radical if it coincides with its self colon. We encode this as the existence of an isomorphism ‘Φ.colon Φ ≅ Φ‘. We then prove a basic characterization of radical preradicals in terms of the vanishing of ‘Φ.r‘ on ‘Φ.quotient‘.
  2. feat(CategoryTheory/Abelian/Preradical): add Stenström’s colon construction for preradicals
    Blake Farman
    Mar 2026
    Given preradicals ‘Φ‘ and ‘Ψ‘ on an abelian category ‘C‘, this file defines their colon ‘Φ : Ψ‘ in the sense of Stenström. Categorically, ‘Φ : Ψ‘ is constructed objectwise as a pullback of the canonical projection ‘Φ.π X : X ⟶ Φ.quotient.obj X‘ along the inclusion ‘Functor.whiskerLeft Φ.quotient Ψ.ι‘.
  3. feat(CategoryTheory/Abelian/Preradical): introduce basic definition of preradicals
    Blake Farman
    Mar 2026
    A preradical on an abelian category ‘C‘ is a monomorphism in the functor category ‘C ⥤ C‘ with codomain ‘𝟭 C‘, i.e. an element of ‘MonoOver (𝟭 C)‘.
  4. feat(RingTheory/IdealFilter): add ideal filters and Gabriel filters
    Blake Farman
    Jan 2026
    Introduces ideal filters on rings and Gabriel filters in mathlib4, including the uniformity conditions (T1–T3), Gabriel composition, and a characterization of Gabriel filters (T4). Preparatory infrastructure for relating Gabriel filters to Giraud subcategories; merged into mathlib4 via PR #33021
  5. feat(RingTheory/IdealFilter): topologies associated to ideal filters
    Blake Farman
    Feb 2026
    Introduces additive and ring topologies on rings arising from ideal filters in mathlib4, including constructions of additive and ring filter bases, characterizations of uniform ideal filters via the existence of a ring filter basis, neighborhood descriptions of the induced topologies, and a proof that the resulting ring topology is linear; provides the topological counterpart to the algebraic theory of ideal filters; merged into mathlib4 via PR #33852.
  6. feat(RingTheory/Ideal): Generalize Submodule.colon to sets
    Blake Farman
    Jan 2026
    Generalize Submodule.colon to accept S : Set M and update the surrounding API; merged into mathlib4 via PR #33390.

Formalization: open pull requests

  1. feat(CategoryTheory/Subobject): kernels of pullbacks of subobjects
    Blake Farman
    Sep 2026
    Adds Subobject.le_pullback_of_comp_eq_zero, Subobject.ofLE_comp_pullbackπ_eq_zero and Subobject.isLimitKernelForkPullbackπ: for a morphism f : X ⟶ Y and subobjects x of X and y of Y, if x.arrow ≫ f = 0 then x is contained in the pullback of y along f, the induced map into that pullback composed with pullbackπ f y vanishes, and if moreover x.arrow is a kernel of f then that map is a kernel of pullbackπ f y. These require only HasZeroMorphisms and HasPullbacks. Open pull request #44223.
  2. feat(CategoryTheory/Abelian): short exact sequences from pulling back a subobject
    Blake Farman
    Sep 2026
    Pulling a subobject B of Y back along an epimorphism f : X ⟶ Y whose kernel is A yields an extension of B by A; this records that as a short exact sequence in an abelian category. Adds shortComplexPullbackπ and shortExact_shortComplexPullbackπ, together with the special case f = cokernel.π A.arrow, which is one direction of the correspondence between subobjects of X containing A and subobjects of the quotient. Builds on Subobject.isLimitKernelForkPullbackπ from #44223. Open pull request #44229.
  3. feat(CategoryTheory/ObjectProperty): closure properties of orthogonals and S. E. Dickson’s theorem
    Blake Farman
    Sep 2026
    Studies how the closure properties of a property of objects P interact with the orthogonal complements P.leftOrthogonal and P.rightOrthogonal and with passage to the opposite category. In a well-powered abelian category with coproducts, if P is closed under quotients, extensions and coproducts then P.rightOrthogonal.leftOrthogonal = P, the hard direction of S. E. Dickson’s characterization of torsion classes. Open pull request #44226.
  4. feat(CategoryTheory/Abelian/TorsionTheory): Introduce torsion theory for abelian categories
    Blake Farman
    Mar 2026
    Introduces torsion theories on an abelian category: a pair of object properties that are each other’s left and right orthogonals. Adds Abelian.TorsionTheory, the typeclasses IsTorsionClass and IsTorsionFreeClass, the torsion theories generated and cogenerated by a property, transport along op and unop, and Dickson’s theorem isTorsionClass_iff: in a well-powered abelian category with coproducts, a class is a torsion class if and only if it is closed under quotients, extensions and coproducts. Open pull request #36744.