Mathematical Sciences Department Teaching Talk - Kenji Kozai, Lesley University

Monday, February 2, 2026
11:00 a.m. to 11:50 a.m.
Location
Floor/Room #
202
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Speaker: Kenji Kozai, Lesley University

Monday, February 2nd

11:00 - 11:50 AM

Stratton 202

Title: Life in a hyperbolic world
Abstract: Euclid’s famous parallel postulate says that given a line in the 
plane and a point not on the line, there is a unique line 
parallel to the first line passing through the given point. 
However, there are other geometries in which this postulate 
is not true. Some are familiar, like the geometry of the 
surface of a sphere, while others, like hyperbolic geometry, 
are less familiar despite being the most “common” geometry 
in many mathematical senses.
In this talk, we will investigate models of hyperbolic 
geometry, including one that can be built by physically 
assembling triangles, to explore its interesting properties and 
to understand some of the surprising consequences of living 
in a hyperbolic world. For example, any two points in an area 
as large as the United States could be within 15 miles of each 
other yet be practically impossible to travel between them. 
Time permitting, we will also overview some of the 
intentional and unintentional ways in which hyperbolic 
geometry arises in real life