On February 28, 2022, Sang-il Oum from IBS Discrete Mathematics Group and KAIST gave a talk at the Discrete Math Seminar on an explicit upper bound of the size of pivot-minor obstructions of graphs of linear rank-width at most k and the size of F-representable minor obstructions of matroids of path-width at most k. The title of his talk was “Obstructions for matroids of path-width at most k and graphs of linear rank-width at most k“.