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A magic eye image. The image is red, gray and black pixels, representing a stereogram. By staring at the image, a Scotty Dog, 鶹's mascot, is revealed in the center.
Magic Eye images like this one reveal hidden shapes and objects when the viewer allows their eyes to shift focus.

When Abstract Problems Take Shape

Mathematician Florian Frick looks at problems as shapes, revealing solutions invisible from a single perspective

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Magic Eye books from the 1990s hid three-dimensional images in what looked like a swirl of dots and colors. At first glance, you see only noise. Change your focus, and suddenly a shape appears.

鶹 mathematician Florian Frick(opens in new window) studies something similar in mathematics. His work explores how problems related to fairness, arrangements and patterns can reveal hidden geometric structure when viewed from the right perspective.

“Mathematics is a kind of mapmaking for abstract worlds,” Frick said. “I enjoy the process of taking an abstract problem and translating it into something that I can reason about visually.” 

Florian Frick

Florian Frick

Frick, an associate professor in the Mellon College of Science(opens in new window) Department of Mathematical Sciences(opens in new window), works at the intersection of geometry, topology and combinatorics. Geometry is the study of shape. Topology looks at the features of shapes that stay the same when they are stretched or bent. Combinatorics studies discrete structures like arrangements, selections and patterns. By bringing these fields together, Frick turns problems that don’t seem geometric into questions about spaces, symmetry and overall structure. He describes it as geometry in action.

This idea is already familiar in everyday language.

“People talk about a ‘political landscape’ to describe a complicated arrangement of views, alliances and tensions,” Frick said. “The phrase suggests that you may want to understand the terrain as a whole, because it may not be enough to look at one position at a time.” 

Frick’s research puts this concept into mathematical terms. For many problems, all possible solutions can be organized into a kind of geometric space. Once that space is built, its shape can reveal information that is not visible from any single point of view.

The shape of fairness 

Consider the problem of fairly dividing rent among roommates. Imagine several roommates are sharing an apartment with different-sized bedrooms. Each room has its own advantages, and each person may value those features differently. The question is: Can the rent be divided among the rooms so that everyone gets a room they prefer without anyone feeling envious? 

At first glance, this sounds like a practical problem. But if you look at it mathematically, it takes on a geometric shape. If a point represents one way of assigning prices to the rooms, in a three-roommate case, the possible rent divisions form a triangle. If there were four roommates, it would form a tetrahedron. More generally, they form a higher-dimensional simplex.

Instead of checking one rent split at a time, mathematicians study the entire space of possibilities at once. “A single proposed rent split may fail. Many proposed splits may fail. But the overall shape of the space of possible splits may force a fair solution to exist somewhere,” Frick said.

Frick and his collaborators explored a twist on this classical problem: What if the preferences of one roommate are unknown? They showed that a fair rent division exists, even without knowledge of the preferences of one of the roommates. Their proof is constructive, providing a recipe for how to actually compute an envy-free rent division. Frick’s work was featured in an episode of PBS’s Infinite Series called .

Geometry beyond the visible 

This type of problem reflects a broader theme in Frick’s research.

“When I look at a problem, I parameterize the space of all possible solutions. I use the word space because it is a geometric object,” Frick said. “And on this geometric object I use geometric and topological tools to find an actual solution. This is particularly powerful because geometry keeps track of global phenomena.” 

Numerous problems across mathematics and its applications are global in this sense, ranging from data science to economics. Frick develops topological and geometric methods to tackle problems further afield. He studies questions about how shapes can be divided, how high-dimensional objects must intersect, how discrete structures can be partitioned and how local constraints can force global behavior. His work connects fair division, combinatorics, convexity, topological methods and related questions in theoretical computer science. A through line in this work is not that the problems come from physical geometry, but that a geometric viewpoint reveals hidden constraints within them.

In that sense, geometry acts like a shift in focus. By giving abstract problems a geometric form, Frick’s work helps uncover the hidden shapes that govern them — and shows how much those shapes can tell us.

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