LSU professor named invited speaker at prestigious International Congress of Mathematicians

Pramod Achar was on a Zoom call with a longtime collaborator when the email arrived.

Both had just been invited to speak at the International Congress of Mathematicians (ICM)—one of the highest honors in the field.

“It was a dramatic moment of shared joy and pride in our scientific achievements,” Achar said. “I was immensely honored. It was certainly the most prestigious speaking invitation I had ever received.”

Achar, the Shirley Blue Barton Professor of Mathematics at Louisiana State University and a Fellow of the American Mathematical Society, is among a select group of mathematicians worldwide chosen to present at the 2026 ICM.

Held once every four years by the International Mathematical Union, the ICM will take place in July 2026 in Philadelphia and is widely regarded as the most prestigious gathering in mathematics. It brings together leading researchers from around the world and serves as the venue where the Fields Medal, often described as the “Nobel Prize of mathematics,” is awarded.

Finding patterns behind complex problems

Achar’s work sits at the intersection of algebra and geometry, in a field known as geometric representation theory.

At its core, the field is about understanding patterns—specifically, how symmetry shapes complex systems. While these ideas are deeply mathematical, they also underpin concepts used in physics, chemistry, and engineering.

One of the key insights behind Achar’s work is that some of the hardest algebra problems can be reimagined in terms of shapes and spaces. By translating abstract problems into geometry, mathematicians can uncover structure that is otherwise hidden.

That approach has led to major advances in a long-standing challenge: understanding “character formulas,” which describe how these systems behave.

For decades, a formula proposed by George Lusztig was widely believed to hold in general. That changed in 2013, when Geordie Williamson discovered a surprising set of counterexamples.

In response, a new framework emerged. Working with collaborators including Simon Riche and Shotaro Makisumi, Achar helped prove a new character formula that replaced the earlier one—an achievement that stands as a central result of his career.

His ICM lecture will highlight this work, along with related advances, including a collaboration with W. Hardesty that resolved a 25-year-old open problem.

From discovery to impact

While the work is theoretical, its long-term impact can be far-reaching.

“Pure mathematics is about discovering patterns that connect ideas that may seem unrelated at first,” Achar said. “History shows that ideas once considered purely theoretical—like non-Euclidean geometry or number theory—can later become essential to technologies like GPS or secure communication. We don’t yet know where today’s mathematics will lead.”

That kind of discovery-driven research is a cornerstone of LSU’s growing national research profile.

“ Pure mathematicians don’t always know where their work will lead—but history shows that today’s abstract ideas can become tomorrow’s essential tools. ”

Invitations to speak at the ICM are rare, and Achar is among the few LSU scholars ever selected. His invitation marks the first time since 1970 that the university has received this distinction, underscoring the depth and impact of LSU’s mathematical research. Notably, Achar is the first LSU faculty member to be invited before attaining the university’s highest faculty rank, Boyd Professor. 

“Prof. Achar’s invitation to speak at the 2026 ICM is an extraordinary honor and a powerful recognition of the depth, originality, and international impact of his scholarship,” said Shea Vela-Vick, professor and chair of mathematics. “This distinction reflects a sustained body of work that has helped shape the direction of his field. We are tremendously proud of Prof. Achar, and this honor speaks both to his standing in the mathematical community and to the strength of the research culture at LSU.”

These distinctions reflect LSU’s research enterprise and its ability to contribute at the highest levels of global scholarship—an essential marker of institutions competing at the forefront of discovery.

Achar’s lecture at the 2026 ICM will place LSU among a select group of universities whose faculty are helping define the future of mathematics.