KCL2026.03

It is a triannual (three-times-a-year) seminar organized by academic genealogy from Professor Dongsu Kim in KAIST Combinatorics Laboratory, which KCL stands for. The aim of this seminar is to bring together active combinatorialists to discuss recent and prospective advances in algebraic and enumerative combinatorics and related areas. The style of talk tends to be less formal.

Program

• March 27 (Friday)

  • 15:00 - 15:50 Invited Talk

    • Speaker Minho Song

    • Title Deograms and Rational Catalan Combinatorics

    • Abstract Arising from Deodhar's work, two families of combinatorial objects called fₖ,ₙ-Deograms and cₖ,ₙ-Deograms were introduced in different mathematical contexts. Although it has been shown that both families are enumerated by the rational Catalan numbers, no conceptual explanation for this coincidence was previously known. In fact, finding a direct bijection between them was posed as an open problem. In this talk, we briefly discuss the origins of these two kinds of Deograms and present a bijective explanation of their equinumerosity. We further specialize to the Fuss–Catalan case and describe explicitly a bijection between Deograms and rational Dyck paths of Fuss–Catalan type. We also discuss several natural problems that remain for future study. This is joint work with Byung-Hak Hwang and Jihyeug Jang.

  • 16:20 - 17:30 Lightning Talks (Up to 10 minutes each)

    • Dongsu Kim

    • Sangwook Kim

    • Jang Soo Kim

    • Seunghyun Seo

    • Taehyun Eom

    • Hojoon Lee

    • Younggwang Cho

  • 18:00 - Dinner

• March 28 (Saturday)

  • 10:00 - 11:30 General Discussion

  • 12:00 - Lunch

Organizer

• Dongsu Kim, GIST