The 11th Annual Pi Mu Epsilon Lecture was given by Prof. Ileana Streinu the Charles N. Clark Professor of Computer Science and Mathematics at Smith College.

The PME lecture took place on **Wednesday, November 1st 2017 at 4:00 pm in Avery 115**.

Preceded by reception (refreshments): 3:30 - 4:00 pm, Avery 348.

Publicity Poster.

## Maxwell's Problem, 150 years later: from bridges to nano-mechanics

Finding a combinatorial characterization for rigid bar-and-joint frameworks in dimensions higher than 3 is an easy-to-state yet elusive, long standing open problem in rigidity theory, originating in two geometry papers from the 19th century of the renowned physicist James Clerk Maxwell. I will summarize our current state of knowledge on Maxwell's problem, and present recent developments leading to a surprising range of applications, from folding robot arms and origami to anayzing the flexibility of molecules and designing materials with unusual mechanical properties.

No advanced prerequisites are necessary. To help build the geometric and kinematic intuitions, the relevant mathematical concepts and techniques will be introduced primarily through physical models and animated graphics.

### About the Speaker

Ileana Streinu is the Charles N. Clark Professor of Computer Science and Mathematics at Smith College. She is a 2012 Fellow of the American Mathematical Society and has been awarded the 2010 Robbins Prize of the American Mathematical Society and the 2004 Moisil Prize of the Romanian Academy. Ileana Streinu won the Robbins Prize of the American Mathematical Society for her algorithmic solution of the carpenter’s rule problem, which asks whether any polygonal chain – a connected series of line segments – can be continuously straightened out in a way that avoids self-intersections. She was awarded the Grigore Moisil Award by the Romanian Academy for estimating the number of distinct planar embeddings of minimally rigid graphs with a given number of vertices.

Professor Streinu's area of research is combinatorial and computational geometry. She enjoys working on both theoretical and applied problems. She employs tools from combinatorics, graph theory, rigidity theory, oriented matroids, linear programming and computational algebraic geometry, to work on problems with applications in computer graphics, graph drawing, robotics, statistics, data visualization and, more recently, computational structural biology. Whether theoretical or applied, geometry lies at the heart of all of Professor Streinu's investigations, providing a unifying thread for her research.

The Pi Mu Epsilon lecture series is made possible through the support of the UNL Mathematics Department, the Nebraska Alpha Chapter of Pi Mu Epsilon and the Nebraska Math Scholars program.

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