Po-Shen Loh

Loh was born in the United States and grew up outside Madison, Wisconsin, attending public schools; he placed third nationally in MATHCOUNTS in eighth grade and later made the US International Mathematical Olympiad team.⁠[1]

His father was a statistics professor and his mother had taught mathematics in Singapore.⁠[2]

He won a silver medal for the US team at the 1999 International Mathematical Olympiad.⁠[3]

In 2002, at a friend’s suggestion, he applied to be a grader for the US team and was voted best lecturer at the end of that June’s training program.⁠[2]

He graduated first in his class from the California Institute of Technology in 2004 and was on the Caltech team that placed seventh of 3,150 teams at that year’s ACMAustralian Community MediaAustralian Community Media (ACM) is an Australian regional and rural news publishing group with more than 100 brands, including The Canberra Times; in 2019 Nine sold it to a company controlled by interests associated with Antony Catalano and Thorney Investment Group.Open the full entry International Collegiate Programming Contest.⁠[4]

That year he received a Hertz Fellowship for doctoral study in mathematics at PrincetonPrinceton UniversityPrinceton University is a private university and Ivy League member in Princeton, New Jersey. Chartered on October 22, 1746 as the College of New Jersey, it moved to Princeton in 1756 and adopted its present name in 1896. Undergraduate education leads to A.B. and B.S.E. degrees and emphasizes small-group discussion, independent research and residential college life. Graduate education spans the humanities, social sciences, natural sciences and engineering. As of October 2026, Christopher L. Eisgruber was president. Its 2026–27 operating budget was $3.407 billion, including $342 million for undergraduate aid.Open the full entry and served as deputy leader of the US team at the International Mathematical Olympiad in Athens, where the team placed second.⁠[5]

Supported by a Winston ChurchillWinston ChurchillSir Winston Churchill (1874–1965) was a British Conservative statesman and writer who served as Prime Minister in 1940–1945 and 1951–1955, led Britain through the Second World War and won the Nobel Prize in Literature in 1953.Open the full entry Foundation Scholarship, he received a master’s degree in mathematics from the University of Cambridge in 2005 and then earned his PhD in mathematics at Princeton University.⁠[6]

He joined the mathematics faculty of Carnegie Mellon University in 2010; after his PhD he again served as deputy leader of the US International Mathematical Olympiad team from 2010 to 2013.⁠[5]

He studies extremal combinatorics, including how overall characteristics of large networks affect their small-scale features.⁠[2]

He co-founded the online learning platform Expii with Ray Li, then a CMU undergraduate, to crowdsource interactive math and science lessons; the company was incorporated in January 2014 and completed a seed round of more than $1 million.⁠[7]

As head coach he led the US team to first place at the 2015 International Mathematical Olympiad in Chiang Mai, Thailand, the team’s first victory since 1994.⁠[8]

Five of the six team members won gold medals and one won silver; as team leader he had moved the summer training program to CMU’s Pittsburgh campus.⁠[3]

He received a National Science Foundation CAREER Award in 2015.⁠[6]

In July 2016 his US team again took first place at the 57th International Mathematical Olympiad in Hong Kong, with all six members winning gold medals; he said the back-to-back wins showed the previous year’s victory was no fluke.⁠[9]

In April 2017 the CMU team he coached placed first for the first time in the 77th William Lowell Putnam Competition, with all three members named Putnam Fellows.⁠[10]

On July 8, 2019, CMU announced that he had received the Presidential Early Career Award for Scientists and Engineers (PECASE), noting that the US team he coached had won three world titles in the previous four years.⁠[11]

The National Science Foundation lists him among the 2016 PECASE recipients.⁠[12]

That month the US team tied with China for first place at the 60th International Mathematical Olympiad in Bath, United Kingdom, with all six members winning gold; it was the team’s fourth first-place finish under his coaching.⁠[13]

On October 13, 2019, he posted “A Simple Proof of the Quadratic Formula” to arXiv, presenting a computationally light and conceptually natural method for solving quadratic equations.⁠[14]

In April 2020 CMU described NOVID, a free app developed by a team of designers, mathematicians, computer scientists and physicists led by him, which combines Bluetooth and ultrasound to track exposure more accurately.⁠[15]

NOVID’s Android version launched on April 7, 2020, and had about 80,000 users by September; the app shows how many relationships separate a user from a positive case and had an official partnership with Georgia Tech.⁠[16]

He appeared on episode 183 of the Lex FridmanLex FridmanLex Fridman is a Soviet-born, US-raised computer scientist and podcast host who works as an MIT research scientist on human-AI interaction and autonomous driving. His Lex Fridman Podcast is known for hours-long conversations with guests including heads of state and technology leaders.Open the full entry Podcast, whose description calls him a mathematician at CMU and coach of the USA International Math Olympiad team; topics included programming competitions, privacy-preserving contact tracing, the Math Olympiad, whether math is discovered or invented, math education, combinatorics, P versus NP and advice for young people.⁠[17]

As of October 2026 he is a professor of mathematical sciences at CMU and academic director of the United States Mathematical Olympiad Program.⁠[18]

On his website he says he served a decade as national coach, speaks in more than 100 cities a year on education after AI, and runs his own EdTech social enterprise.⁠[1]

His younger brother and sister are also Caltech graduates, and he met his future wife on the first day of Caltech orientation.⁠[4]

Personal website: Public link: https://www.poshenloh.com/ (opens in a new window)⁠[17]

X: Public account: https://x.com/poshenloh (opens in a new window)⁠[1]

LinkedInLinkedInLinkedIn is a social networking platform for professionals. It was founded in 2002 by Reid Hoffman and others, launched in 2003, and listed on the New York Stock Exchange in 2011; after Microsoft acquired it for approximately $26.2 billion in 2016, it became a wholly owned Microsoft subsidiary. Its revenue comes from membership subscriptions, advertising, and recruitment solutions.Open the full entry: Public profile: https://www.linkedin.com/in/poshenloh (opens in a new window)⁠[1]

YouTubeYouTubeYouTube is Google’s video-sharing and creator platform, founded in 2005 by Steve Chen, Chad Hurley, and Jawed Karim and acquired by Google in 2006. Built around video uploading, viewing, and creator earnings, the platform has developed Shorts, YouTube Music, Premium, YouTube TV, and products for children, and is headquartered in San Bruno, California, United States.Open the full entry: Public channel: https://www.youtube.com/channel/UCf78EJOm4wQ4xXwSS15PuxQ (opens in a new window)⁠[1]

Carnegie Mellon University: Official website: https://www.cmu.edu/ (opens in a new window)⁠[18]

Expii: Official website: https://www.expii.com/ (opens in a new window)⁠[9]