On November 12, 2021, at 2 pm, Assoc. Prof. Dr. Borislav Yordanov from the DUMF section will give an introductory public lecture on Lack of global solutions to the Cauchy problem for the semilinear wave equation. Abstract Due to the epidemiological situation, the lecture will be online in the Zoom room at https://us02web.zoom.us/j/83662947293?pwd=ekRubytueVBnMzhHR2VXNEJ5V09DUT09 Meeting ID: 836 6294 7293 Passcode: 958735