Tribute to Jim Simons by Emmanuel Ullmo

When I became the director of IHES in 2013, one of my challenges was to maintain the high-quality of our relationships with the Institute’s main sponsors, starting with Jim and Marilyn Simons, our greatest donors.

Jim, a brilliant mathematician and a specialist in differential geometry, knew IHES very well, which he first visited in the 1970s. On scientific matters, he had very close ties with the two directors who came before me at the Institute. Jim distinguished himself on topics directly linked to the research carried out by Marcel Berger, who was a broad spectrum Riemannian geometer and the director of IHES from 1985 to 1994. As head of the mathematics department of the State University of New York in Stony Brook, now the Stony Brook University, Jim had also been a mentor to Jean-Pierre Bourguignon, and invited him there. I come from another specialty, algebraic and arithmetic geometry, so I first knew Jim mainly as a major donor, especially as regards basic science. Which makes me even more grateful to him for the trust he placed in me, and the unfailing personal support he gave me.

Having made a considerable mark on mathematics and finance, he distinguished himself once again, this time as a philanthropist, together with Marilyn with whom he co-founded the Simon foundation. Jim wasn’t only exceptionally generous, he also became personally involved in the institutions he championed, by providing them with advice and expertise, giving them his time and introducing them to his network of contacts. In 2024, I was very honored to see Jim joining the IHES Board of Directors and taking part in our twice yearly meetings, even though they were held in the morning in France when it was still dark in New York! The Board members all remember him logging on at four o’clock in the morning, coffee in one hand, cigarette in the other. When he could, Jim even came to France to attend the Board meeting in person. It was to be his last trip to the Institute, with Marilyn, in May 22, less than two years ago.

In addition to the very significant financial support he gave IHES, he was constantly seeking to help the Institute in any way he could, both in Europe and in the United States. Readily available and always loyal, Jim and Marilyn attended all the gala dinners of Friends of IHES, our partner organization in the United States, and they personally hosted several events organized for our donors. They also took part in fundraising events in California, Boston and in London. With his trademark humor and straight talk, Jim directly approached potential supporters and encouraged them to fund us in turn. In fact, many of our donors discovered the Institute and supported us, thanks to him. On several occasions, Jim and Marilyn also pledged challenge gifts and matching gifts to IHES or Friends of IHES, with specific targets to be met for the donations to be fulfilled – a fantastic opportunity for us to extend our network and approach new donors. In doing so, they took us to another level and helped us with our philanthropy endeavors, way beyond monetary gifts.

In 2021, Jim and Marilyn joined the Friends of IHES Board of Directors, before taking over as Co-Chairs in 2022. It was in that context that Jim decided to launch an endowment fund for IHES in the United States, in addition to the Institute’s endowment fund in France, with more dynamic management from an investment committee he initially led. This project, which will have a lasting impact on the Institute, has been an instant success and is now a real boost for Friends of IHES’ fundraising operations.

In the course of his three careers as mathematician, pioneer of quantitative finance and philanthropist, Jim was a truly charismatic and extraordinary visionary. He leaves a huge gap in our community but those who knew him are also filled with gratitude. The legacy he has left is immense.