Hikaru Dávid Jitsukawa

Welcome to my website! My name is Hikaru Jitsukawa, and I am a doctoral student studying mathematics at Tufts University. My research interests broadly concern geometric group theory, particularly the geometries of CAT(0) and hyperbolic groups, boundaries of groups, and Coxeter Groups. My current supervisor is Dr. Kim Ruane.

Over the past several years, I have also worked on and mentored projects about the quasi-isometric rigidity of groups, algebraic combinatorics, and the interactions between 20th century continental European philosophy and mathematics. I am always open for collaboration, please do not hesitate to email me about any of these topics.

All views expressed on this page are the author's own and do not reflect those held by Tufts University or its affiliates. 

Last updated: February 2026

Upcoming Travel:

• TBD

Writing:

• Quasi-isometric rigidity of the integers: an elementary primer, with Tarik Aougab, Kim Ruane (2026, ArXiv)

• The Geometry of the Bruhat Order in Affine S_3, Undergraduate Thesis (Revised 2024, Full Text PDF)

• The Stages on Which we Play: Critical Phenomenology and Theatrical Interpellation, Undergraduate Thesis (Revised 2023, Full Text PDF)

• Experimental Results on Potential Markov Partitions for Wang Shifts, with Harper Hults, Casey Mann, Justin Zhang (2023, ArXiv)

Talks:

• Orientalism and the Historiography of Mathematics, informal talk at Monday Math Meeting at Tufts University (2026, Rough Slides, Booklet)

• The Banach-Tarski Paradox, informal talk at Monday Math Meeting at Tufts University (2025, Rough Notes)

• Workshop for Potential Literature: Surrealism and Proceduralism in the History of Mathematics, informal talk at Monday Math Meeting at Tufts University (2025, Rough Notes)

• To Collapse into Nothingness: An Introduction to Mathematical Structuralism, informal talk at Monday Math Meeting at Tufts University (2024, Rough Notes)

• A Geometric Partial Ordering on Affine S_3, presentation at Haverford College (2023, Slides)

• Turning on Frankenstein: Seams, Sutures, and Gendered Embodiment, presentation at Haverford College (2023)

• A Markov Partition for the Penrose Shift, poster presentation at the Joint Mathematics Meetings, presentation at the AMS contributed paper session on Dynamical Systems and Ergodic Theory (2023)

• Symmetries of Shift Spaces and Symbolic Representations, presentation at University of Washington: Bothell (2022, Slides)

Courses

• Fall 2026- Math 0015: Mathematics in Antiquity

  • Tufts University Department of Mathematics

• Spring 2026- Math 0019: Mathematics of Social Choice

  • Course Resources Website (Coming Soon!)

  • Tufts University Department of Mathematics

• Summer 2025- Math 0010: Introductory Special Topics - Machine Learning/ Python

  • Tufts University Department of Mathematics

• Summer 2024- Math 0010: Introductory Special Topics - Machine Learning/ Python

  • Course Resources Website (Coming Soon!)

  • Tufts University Department of Mathematics

Teaching Assistantships

• Fall 2025- Math 0032: Calculus I Practicum (3 Sections)

  • Tufts University Department of Mathematics

• Spring 2025- Math 0032: Calculus I Practicum (3 Sections)

  • Tufts University Department of Mathematics

• Fall 2024- Math 0070: Linear Algebra Practicum (3 sections)

  • Tufts University Department of Mathematics

• Spring 2024- Math 0032: Calculus I Practicum (3 sections)

  • Tufts University Department of Mathematics

• Fall 2023- Math 0032: Calculus I Practicum (3 sections)

  • Tufts University Department of Mathematics

Organization:

• President of Tufts Organization for Graduate Students in Mathematics

  • May 2025 - Present

• Organizer of the Tufts Monday Math Meeting Talk Series

  • September 2024- December 2025

• Secretary of Tufts Organization for Graduate Students in Mathematics

  • May 2024- April 2025

Outreach:

• Mentor for Tufts Directed Reading Program

  • Project: Jacques Derrida's Edmund Husserl's Origin of Geometry: An Introduction

  • January 2026- April 2026

• Mentor for Reading Course on Metric Geometry

  • Project: Parts I and II of Bridson and Haefliger's Metric Spaces of Non-Positive Curvature

  • September 2025 - Present

• Mentor for Tufts Directed Reading Program

  • Project: Introduction to the Cohomology of the Flag Variety

  • September 2025 - December 2025

• Mentor for Tufts Directed Reading Program

  • Project: Alain Badiou's Being and Event and Mathematical Philosophy

  • January 2024 - April 2024

Textbook Resources:

• Partial Notes on Sections I and II of  Metric Spaces of Non-Positive Curvature by Martin Bridson and André Haefliger (Website Coming Soon)

Miscellaneous Notes:

• Notes on Kim Ruane's mini-course "Boundaries of Groups" (Notes) (Talk Part 1) (Talk Part 2)

• Notes on Robbie Lyman's mini-course "Bass-Serre theory: groups acting on trees" (Notes) (Talk Part 1) (Talk Part 2) (Talk Part 3)

• "What Does Blackout Poetry Teach Us About Intersectionality?": A zine-style report on using poetry to do philosophy, engaging directly with the works of Audre Lorde, Jennifer Nash, and Tressie McMillan Cottom. Written with Lara Deuber, Uba Ogidi, and Sophia Vaidya. (PDF)

• "Braid Groups and Knot Theory": An expositional paper on the Artin Braid Group written with Martin Vollmayr-Lee and Tianbo Yang during an undergraduate abstract algebra course. (PDF)

• "An Exploration of the Dimension of the Cantor Set": An expositional paper on the Hausdorff dimension written during an undergraduate real analysis course. (PDF)

I am happy to write letters of recommendation for any students who have taken a class with me or worked with me extensively. I would be especially excited to write recommendations for projects that bridge between mathematics and the humanities. If you believe that I would be a good judge of your skills, then please email me at least 4 weeks before the submission deadline with the following:

1. What appeals to you about this opportunity? Why are you passionate about it, or why do you think you are especially suited for it?

2. What skills would you want me to mention? How did you develop these skills during our class?

3. A CV or Resumé.

4. A link, email address, and deadline for submission.

And remember to write all your recommenders a thank you email or note with updates afterward.

In pursuing justice through the academy, it is important to address that every intellectual pursuit, including mathematics, has a legitimating position in the power structures of its society. As such, I am not willing to write recommendation letters for projects funded by or involving, either directly or indirectly:

• Militaries, intelligence agencies, or organizations in close relation to these.

• Prisons, policing, and private security agencies.

I urge my colleagues in positions of greater stability and authority to do the same and more.

Thank you to Professor Aougab for allowing me to use this framework.

For any further details, scripts, or other materials for the entries below, please feel free to email me.

Sketches and Short Plays:

• Singing in the Rain (2023)

  • Characters: 2. Runtime: 4 Minutes. Genre: Slapstick, Deadpan.

  • Plot: The iconic musical number "Singing in the Rain" is told from the perspective of the technician holding the hose. Audience members are encouraged to bring raincoats or other waterproof gear.

• The Ends of Things (2023)

  • Characters: 4. Runtime: 5 Minutes. Genre: "Mor(t)ality Play"

  • Plot: Orpheus and Euridice discuss metaphor on the walk back from the underworld. How does death change the things we mean to say? 

• Confession (2022)

  • Characters: 7. Runtime: 7 Minutes. Genre: Blue Comedy. 

  • Plot: An actor is forced to quit performing after embezzling the prop budget for a very personal purpose. They attempt to clear their name to the audience.

• The Button (2022)

  • Characters: 2. Runtime: 8 Minutes. Genre: Theater of the Absurd.

  • Plot: Two friends on a road trip are confronted by the frivolous yet looming threat of an explosion. What purpose is there to political violence? Who can enact it?

• Adopt These Terrible Dogs (2022)

  • Characters: 3. Runtime: 4 Minutes. Genre: Dark Comedy. 

  • Plot: A holiday pet adoption advertisement goes awry, as all the remaining dogs have nuanced and challenging behavioral quirks. 

Music:

• mens volleyball, with Harrison Lennertz and Matt Curran (Bandcamp).

Other:

• The Life and Works of Remy the Rat (2026)

  • Ratatouille Dinner Party Cooking Zine (Printable PDF)

  • With Sam Cote

• Comic Adaptation of "The Ends of Things" (2025)

  • Sample Pages (Sample PDF)

  • With Sam Cote

• Altoids Tin Chalk Holder (2024)

  • A 3d print that turns a standard-size Altoids tin into a chalk holder for four pieces of Hagoromo chalk. (Documents)

•  Your Average Life (2023)

  • This Arduino program counts down the number of heartbeats remaining in the user's lifetime given a number of statistical factors.

  • Compatible with the Arduino serial display.