This is not your typical mathematics colloquium.

Renowned for outing a Soviet-connected hacker while working at Livermore National Lab in the late 1980s, Dr. Clifford Stoll, who is an astronomer, author and teacher, will present a cybersecurity talk **“Fun With Low Dimensional Topology”** in Kidder Hall 364 from 4-5 p.m. on Thursday, April 5, 2018. Stoll is Chief Bottle Washer at Acme Klein Bottles.

Prerequisites: A curious mind and a sense of humor.

As part of the Department of Mathematics Undergraduate Colloquium, Stoll will discuss the Klein bottle and related things, which is catnip for interesting minds across all disciplines. You will see novel twists in a Klein bottle as well as several topological manifolds hot from the annealing oven. This is a mathematics seminar without equations, but *with door prizes!*

In topology, a branch of mathematics, the Klein bottle is an example of a non-orientable surface of Euler characteristic 0 that has no inside or outside. In other words, it is a mathematical object that intersects itself. Mathematicians add a fourth dimension at this point to enable the intersection to proceed without tearing a hole in the otherwise continuous mathematical surface. The adding of a fourth dimension is considered impractical, as only three such directions appear to fit into our normal conception of space, which for this reason is called 3D space.

While the Klein Bottle is a mathematical construct, Stoll is CEO of Acme Klein Bottles, a manufacturer of custom, hand-blown glass bottles.

He will present a second talk, **“Stalking the Wily Hacker,"** on Friday, April 6, 10-11 a.m. in Kelley Engineering, room 1001. About 30 years ago back in the early days of the Internet, a group of hackers systematically broke into military computers attracting the interest of the NSA, FBI, and the CIA. While working as an IT manager at the Lawrence Berkeley National Laboratory in 1986, Stoll investigated matters that led to the capture of notorious KGB hacker Markus Hess. He details the story in his book, *The Cuckoo's Egg*," as well as in a PBS Nova show. Come hear the story live!

To see Stoll’s energy and humor first hand, check out the first minute or two of this TED Talk to get a flavor of his “wildly energetic” style that includes a sprinkling of anecdotes, observations, asides—and a science experiment, according to his TED webpage. It has been translated into 27 languages and has been viewed more than two million times.

By his own definition, he's a true scientist: "Once I do something, I want to do something else.”

Stoll has written three books as well as technology articles in the non-specialist press, such as *Scientific American* on the Curta mechanical calculator and the slide rule. He has worked at China's Purple Mountain Observatory, Space Telescope, Kitt Peak Observatory, and the Keck Observatory in Hawaii. He is a frequent guest on the YouTube Numberphile channel.

A native of Buffalo, New York, Stoll earned a bachelor’s degree in astronomy in 1973 from the University at Buffalo where he also worked in the university's electronic music laboratory and was mentored by Robert Moog, who invented the Moog synthesizer. Stoll earned his Ph.D.in planetary physics from the University of Arizona in 1980.

Hosted by the Departments of Mathematics and Computer Science, this event is free and open to all.