# Christer Oscar Kiselman's mathematical
ancestors

I defended my Ph.D. thesis at Stockholm University on 1966 December
03. My advisor there during the years 1961—1964 was
I attended his lectures on partial differential equations in the fall
of 1961 and the spring of 1962, and then his lectures on analytic
functions of several complex variables in the fall of 1962 and the
spring of 1963. During the academic year 1965-66, I was invited as a
Member at the Institute for Advanced Study in Princeton, NJ, and Lars
was there, so our relation could go on.
Lars Hörmander defended his Ph.D. thesis at Lund University on 1955
October 22. His advisor, as first registered in the Mathematics
Genealogy Project, was

Riesz was professor at Lund University and got his Ph.D. in 1912 at the
University of Budapest with
as advisor. Fejér got his Ph.D. at the
University of Budapest in 1902. His advisor was
Schwarz received his Ph.D. in 1864. His advisor was
His name was written Weierstrass in the nineteenth century and
nowadays most often Weierstraß.
Schwarz attended Weierstrass's lectures on Integral Calculus in 1861.
Weierstrass was awarded an honorary doctorate by the University of
Königsberg in 1854, so we cannot say he had a Ph.D. advisor. However,
he studied mathematics for Gudermann in 1838—1840. In a more recent
version of the Mathematics Genealogy
Project, Gudermann is considered to be the advisor of Weierstrass,
which makes it possible to go back to Gauss and Pfaff and even
further...

Originally only Marcel Riesz was listed in the Mathematics Genealogy
Project as an advisor of Lars Hörmander, and I had followed this link
above. Later Lars Gårding (1919-03-07 — 2014-07-07) was
introduced as a second advisor. In a publication Lars Hörmander
wrote:

"When I defended my thesis in 1955 Lars Gårding was my advisor for
Marcel Riesz had retired in 1953 and been in the US since then."
(Hörmander 2003:61)

*Reference*

Hörmander, Lars. 2003. A tribute to Laurent
Schwartz. **In:** *Laurent Schwartz (1915—2002)*.
Supplément au numéro 98 de la Gazette des mathématiciens,
pp. 59–62. Paris: Société mathématique de France.

*Acknowledgment:* This information is partly based on the
Mathematics Genealogy Project of Harry B. Coonce. Thank you!

invited me to join him in
Nice during the academic year 1967–1968. He influenced me in
many ways, mathematically as well as culturally. I have tried to sum
up my memories about him and our year together in two essays,
in French and English. The first-mentioned was rejected
by *La Gazette des Mathématiciens* on 2020 June 26. The
second was published online in *Complex Analysis and Operator
Theory*, volume **14**, issue 7, on 2020 September 14.

Christer Oscar Kiselman, 2022 September 26. To Christer's home page. Amber addresses:
kiselman@it.uu.se, christer@kiselman.eu