Jordan Ellenberg, the John D. MacArthur Professor of Mathematics at the University of Wisconsin-Madison, gave the 2016 Howard Rowlee Lecture in 115 Avery Hall at 4:00pm on Thursday, March 17, 2016.

## There is no such thing as public opinion: The mathematics of elections, public policy, and slime molds

### Abstract

Public opinion polls routinely show that large majorities of Americans support cutting spending and oppose raising taxes. But when lists of government programs are presented one by one, cuts in each program face majority opposition. What's going on here? A typical account is that Americans are irrational thinkers who want a free lunch, with low taxes and big government programs for all. The truth is more complicated. In fact, trying to put together the opinions of a heterogeneous population can lead to paradoxical results, even when the individuals involved are perfectly rational. The math that explains the puzzling polling on the budget—first discovered by Condorcet in the midst of the French Revolution, and culminating in the Nobel-winning work of Kenneth Arrow—also explains the vexingness of the Bush-Gore-Nader clash in Florida in 2000, the difficult GOP primary of 2016, and and the apparently irrational decisions made by slime molds, primitive brainless creatures who biologists believe to be similar in certain respects to electorates.

### About the Speaker

Jordan Ellenberg is the John D. MacArthur Professor of Mathematics at the University of Wisconsin-Madison. His research centers on the fields of number theory and algebraic geometry, the parts of mathematics which address fundamental questions about algebraic equations and their solutions in whole numbers. Ellenberg’s work has uncovered new and unexpected connections between these subjects and algebraic topology, the study of abstract high-dimensional shapes and the relations between them. Ellenberg was a plenary speaker at the 2013 Joint Mathematics Meetings, the largest mathematics conference in the world, and he has lectured about his research around the United States and in ten other countries. He has held an NSF-CAREER grant and an Alfred P. Sloan Fellowship, in 2013 he was named one of the inaugural class of Fellows of the American Mathematical Society and in 2015 he was named a Guggenheim Fellow.

Ellenberg has been writing for a general audience about math for more than fifteen years; his work has appeared in the New York Times, the Wall Street Journal, the Washington Post, Wired, The Believer, and the Boston Globe, and he is the author of the “Do the Math” column in Slate. His 2014 book How Not To Be Wrong was a New York Times bestseller.

The Howard Rowlee Lecture Series is made possible through a generous donation by Mr. Howard E. Rowlee, Jr., a Lincoln resident and friend of the department, who has established a fund at the University of Nebraska Foundation to support research in mathematics. The Howard Rowlee Lecture is an annual event which seeks to bring internationally acclaimed scholars in the mathematical sciences to UNL to promote public understanding of mathematical research and to stimulate the environment for mathematics research at UNL.