<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto">The following talk at the Math Colloquium tomorrow can be of interest to many on this list.<div dir="ltr"></div><div><br></div><div>Date/time: 3/26, 3pm</div><div><br></div><div>Room: E202</div><div><br></div><div><div dir="ltr" style="-webkit-text-size-adjust: auto; color: rgb(33, 33, 33);">Speaker: Rachel Greenfeld (Northwestern)</div><div dir="ltr" style="-webkit-text-size-adjust: auto; color: rgb(33, 33, 33);"><br></div><div dir="ltr" class="x_elementToProof" style="-webkit-text-size-adjust: auto; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif;">Title: Integer distance sets</div><div dir="ltr" class="x_elementToProof" style="-webkit-text-size-adjust: auto; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif;"><br></div><div style="-webkit-text-size-adjust: auto;"><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif;">Abstract: A set in the Euclidean plane is called an integer distance set if the distance between any pair of its points is an integer. All so-far-known integer distance sets have all but up to four of their points on a single line or circle; and it had long been suspected, going back to Erdős, that any integer distance set must be of this special form. In a recent work, joint with Marina Iliopoulou and Sarah Peluse, we developed a new approach to the problem, which enabled us to make the first progress towards confirming this suspicion. In the talk, I will discuss the study of integer distance sets, its connections with other problems, and our new developments.</span></div></div></body></html>