On March 13, 2026 (Fri), the 2026 POSTECH Mathematics Open Lecture Series / APCTP was held at the Event Hall on the first floor of Change Up Ground. The event brought together POSTECH members and citizens of Pohang and ran from 1:59 PM to 5:00 PM.

 The program began with opening remarks and an introduction by Prof. Jae-Hun Jung, Chair of the Department of Mathematics. Ms. Sori Kim from APCTP then introduced the center. This was followed by a lecture by Prof. Cheol-Hyun Cho (POSTECH Mathematics) titled “Mirror Symmetry: Geometry and Algebra in Reflection,” and a talk by Dr. Kyoung-Min Kim (Asia Pacific Center for Theoretical Physics), “Symmetry and the Beauty of Physics,” which highlighted the deep connections between mathematics and physics.

 The Pi Day event attracted broad participation from POSTECH members (including undergraduate and graduate students), citizens of Pohang, and students from Gyeongbuk Science High School and Yuseong Girls’ High School. Before the main program began, Prof. Jung engaged the audience with a Pi Day–related question, “How many digits of π do you know?” This interactive moment, particularly the enthusiastic participation of students from Gyeongbuk Science High School, created a lively atmosphere. Refreshments were provided, and commemorative gifts from the Department of Mathematics and APCTP were awarded to participants who correctly answered quiz questions throughout the event.

 After the lectures, an interactive activity program jointly organized by the POSTECH Mathematics Student Council and APCTP took place. Through the APCTP quiz and the activity “Can You Interpret This Pi?” participants experienced Pi Day firsthand and gained an enjoyable understanding of its meaning. The high level of engagement from local citizens added further energy to the event.

 At the conclusion of the program, circular pizzas symbolizing 3.14 and beverages were served. Participants enjoyed a meaningful time that made mathematics feel more approachable, and the event concluded successfully.