&quot;A consensus emerged that the highlight of the workshop was a lecture on 9 December by Kiran Kedlaya, an arithmetic geometer from the University of California, San Diego. He zeroed in on a result from a 2008 paper by Mochizuki5 that linked the statement of the abc conjecture to another branch of maths called <i>topology</i>. The link was immediately recognised as a crucial step in Mochizuki’s grand strategy. &quot;