Jon Folkman
... that Paul Erdős challenged Jon Folkman to solve mathematical problems immediately after Folkman's surgery for brain cancer?
... that <a href="./Paul_Erdős" id="mwA9Y" rel="mw:WikiLink" title="Paul Erdős">Paul Erdős</a> challenged <b id="mwA9c"><a href="./Jon_Folkman" id="mwA9g" rel="mw:WikiLink" title="Jon Folkman">Jon Folkman</a></b> to solve <a href="./Mathematical_problem" id="mwA9k" rel="mw:WikiLink" title="Mathematical problem">mathematical problems</a> immediately after Folkman's surgery for brain cancer?