Jae Choon Cha is Professor of Mathematics and Mueunjae Chair Professor at POSTECH.  He is also an Affiliate Professor at KIAS.

  1. Milnor’s question on transfinite invariants, Knotted Embeddings in Dimensions 3 and 4, February 15, 2018, CIRM, Marseille, France.
  2. Milnor’s transfinite invariant problem for 3-manifolds, The 13th East Asian School of Knots and Related Topics, January 31, 2018, Daejeon, Korea.
  3. $L^2$-acyclic bordism and knot concordance, December 19, 2017, University of Regensburg, Regensburg, Germany.
  4. Transfinite Milnor invariants of 3-manifolds, December 8, 2017, University of Warsaw, Warsaw, Poland.
  5. Transfinite Milnor invariants of 3-manifolds, December 4, 2017, Max Planck Institute for Mathematics, Bonn, Germany.
  6. 4-dimensional $L^2$-acyclic bordism of 3-manifolds, November 21, 2017, University Paris Diderot (Paris 7), Paris, France.
  7. Cheeger-Gromov $L^2$ rho-invariants and low dimensional topology, MFO workshop: Interactions between Low-dimensional Topology and Complex Algebraic Geometry, October 23, 2017, Oberwolfach, Germany.
  8. Milnor invariants and rational Whitney towers, September 25, 2017, St. Petersburg State University, St. Petersburg, Russia.
  9. Hirzebruch-type invariants of Cheeger-Gromov and low dimensional topology, Oberseminar at Max Planck Institute for Mathematics, August 31, 2017, Bonn, Germany.
  10. Bordism, chain homotopy, and Cheeger-Gromov $\rho$-invariants, Quantitative Geometry and Topology — a special session in Mathematical Congress of America 2017, July 25, 2017, Montreal, Canada.
  11. 다양체의 위상수학과 디스크 임베딩 (Topology of manifolds and disk embedding), 무은재 석좌교수 기념강연 (Mueunjae Chair Professor Lecture), May 22, 2017, POSTECH, Pohang, Korea.
  12. Whitney towers in a rational homology ball, Invariants in Low-dimensional Topology, May 12, 2017, KIAS, Seoul, Korea.
  13. Milnor invariants and rational Whitney towers, April 19, 2017, Indiana University, Bloomington, Indiana, USA.
  14. $L^2$-acyclic bordism and Whitney towers, The 12th East Asian School of Knots and Related Topics, February 14, 2017, University of Tokyo, Japan.
Research on Geometric Topology
  • Figure eight on my caffè latteInterplay between topology of dimension 3 and 4
  • Knot theory: placement problems of manifold pairs
  • Related algebra, homotopy theory, and $L^2$-invariants

KnotInfo: a table of invariants of classical knots, maintained by Charles Livingston and me.

Selected Papers

List of all papers

  1. The bipolar filtration of topologically slice knots (with Min Hoon Kim)
    • Preprint arxiv:1710.07803 (23 pages) 
  2. Unknotted gropes, Whitney towers, and doubly slicing knots (with Taehee Kim)
    Transactions of the American Mathematical Society, to appear.
    • Preprint arXiv:1612.02226 (43 pages)
  3. Rational Whitney tower filtration of links
    Mathematische Annalen 370 (2018), no. 3, 963–992.
    • Published • Preprint arXiv:1609.05161
  4. Whitney towers and abelian invariants of knots (with Mark Powell and Kent E. Orr)
    • Preprint arXiv:1606.03608 (34 pages)