東北大学の横山です． 直前の方で大変恐縮ですが，以下の通りセミナーを開催いたしますのでご案内いたします．

https://sites.google.com/view/sendai-logic/

日時：4月4日(金)15:00〜 場所：東北大学理学研究科合同A棟801号室 (zoom配信あり) 講演者：Andrew Arana (Université de Lorraine, Archives Poincaré)

Title: Varieties of reversals Abstract: Reverse mathematics has become one of the most important subjects of mathematical logic. It has a rich domain of problems arising from ordinary mathematics, as well as a programmatic orientation. To put it briefly, its results seem to matter not only for logic but also for ordinary mathematics. Yet there are several different accounts of why it matters, of what a reversal tells us. I want to discuss a few of these.

オンライン参加を希望される方は横山までご連絡いただきますようよろしくお願いいたします

どうぞよろしくお願いいたします．

横山啓太 -- Keita Yokoyama Mathematical Institute, Tohoku University [email protected]