Email: callem “at” sas “dot” upenn “dot” edu

Office: 4C1

Pronouns: she/her/hers


I am a second year graduate student and NSF graduate fellow at the University of Pennsylvania, advised by Mona Merling. I’m generally interested in algebraic topology and homotopy theory, and I also have an interest in mathematical visualization and communication. I graduated from Reed College in 2020, where I got a BA in Mathematics and spent a lot of time in the Philosophy Department.

Aside from academics, I enjoy practicing aerial acrobatics and making artwork (some of which you can see here). I am also very passionate about creating an inclusive, diverse mathematical community. To paraphrase this post by the AMS blog Inclusion/Exclusion, I believe that we must work towards an environment in which any person who wants to be a mathematician, can. We must work against the aspects of academia and STEM that sustain a racist system, and we must work to change mathematics itself to that it actually serves Black and Indigenous communities.



My name is pronounced “mack-SEEN eh-LEH-na CAH-shay.”

I run a math blog with Thomas Brazelton and Andres Mejia. I also have a running list of fun activities related to topology and geometry.

I was featured on What is a Reedie? where I talk a bit about myself, my undergraduate thesis, and my Reed College experience. Read my full responses here.

I’ve adopted a polyhedron, called the Xinegon, which you can see here. The Xinegon has 631 siblings, with f-vector (9, 17, 10). I like that she has some triangular faces, some quadrilateral faces, and some pentagonal faces.

Upcoming Travel and Conferences

Past Travel and Conferences

  • July 2021: PCMI’s “Illustrating Mathematics” Graduate Summer School; online.
  • April 2021: Underrepresented Students in Algebra and Topology Research Symposium (USTARS); online.
  • April 2021: Graduate Student Topology and Geometry Conference (GSTGC); online.
  • November 2020: Binghamton University Graduate Conference in Algebra and Topology (BUGCAT); online.
  • September 2020: Cascade Topology seminar; online.
  • Summer 2020: Algebraic Topology Bridge Summer Workshop; online.
  • Summer 2020: Graduates Reminisce Online on Topology seminar (GROOT); online.
  • January 2020: Nebraska Conference for Undergraduate Women in Mathematics (NCUWM); University of Nebraska-Lincoln, NE.
  • May 2019: Women and Mathematics (WAM); Institute for Advanced Study, NJ.
  • January 2019: Joint Mathematics Meetings (JMM); Baltimore, MD.
  • November 2018: Undergraduate Mathematics Symposium (UMS); University of Illinois at Chicago, IL.
  • November 2018: Northwest Undergraduate Mathematics Symposium (NUMS); Willamette University, OR.