Mikael Rørdam (born 7 January 1959, Copenhagen) is a Danish mathematician,^[1] specializing in the theory of operator algebras and its applications.

Rørdam graduated with master's degree from the University of Copenhagen in 1984.^[2] He received his PhD from the University of Pennsylvania with thesis The theory of unitary rank and regular approximation under the supervision of Richard Kadison.^[3] In the spring of 1988 Rørdam was a postdoc at the University of Toronto. At Odense University he was an Adjunkt (assistant professor) from 1988 to 1991 and a Lektor (associate professor) from 1991 to 1997. He was a Lektor at the University of Copenhagen from 1998 to 2002 and full professor from 2002 to 2007 at the University of Southern Denmark. Since 2008 he is a full professor at the University of Copenhagen.^[2]

Rørdam was elected a member of the Royal Danish Academy of Sciences and Letters in 2004.^[2] He was an invited speaker of the International Congress of Mathematicians in 2006 in Madrid. He was a member of the board of the Mittag-Leffler Institute from 2010 to 2016. He was a plenary speaker at the International Workshop on Operator Theory and its Applications (IWOTA) in 2018 in Shanghai.^[2]

• Rørdam, Mikael (1991). "On the structure of simple C*-algebras tensored with a UHF-algebra". Journal of Functional Analysis. 100 (1): 1–17. doi:10.1016/0022-1236(91)90098-P. ISSN 0022-1236.
• Rørdam, Mikael (1992). "On the structure of simple C*-algebras tensored with a UHF-algebra, II". Journal of Functional Analysis. 107 (2): 255–269. doi:10.1016/0022-1236(92)90106-S.
• Blackadar, Bruce; Rørdam, Mikael (1992). "Extending states on preordered semigroups and the existence of quasitraces on C*-algebras". Journal of Algebra. 152 (1): 240–247. doi:10.1016/0021-8693(92)90098-7. ISSN 0021-8693.
• Rørdam, M. (1995). "Classification of Certain Infinite Simple C*-Algebras". Journal of Functional Analysis. 131 (2): 415–458. doi:10.1006/jfan.1995.1095.
• Kirchberg, Eberhard; Rørdam, Mikael (2000). "Non-simple purely infinite C*-algebras". American Journal of Mathematics. 122 (3): 637–666. doi:10.1353/ajm.2000.0021. S2CID 18204703.
• Kirchberg, Eberhard; Rørdam, Mikael (2002). "Infinite Non-simple C*-Algebras: Absorbing the Cuntz Algebra O_∞". Advances in Mathematics. 167 (2): 195–264. doi:10.1006/aima.2001.2041.
• Rørdam, M. (2002). "Classification of Nuclear, Simple C*-algebras". Classification of Nuclear C*-Algebras. Entropy in Operator Algebras. Encyclopaedia of Mathematical Sciences. Vol. 126. pp. 1–145. doi:10.1007/978-3-662-04825-2_1. ISBN 978-3-642-07605-3.
• Rørdam, Mikael (2003). "A simple C*-algebra with a finite and an infinite projection". Acta Mathematica. 191 (1): 109–142. arXiv:math/0204339. doi:10.1007/BF02392697. S2CID 11212596.
• Rørdam, Mikael (2004). "The stable and the real rank of ${\displaystyle z}$-absorbing C*-algebras". International Journal of Mathematics. 15 (10): 1065–1084. doi:10.1142/S0129167X04002661. 2004
• Rørdam, Mikael; Winter, Wilhelm (2010). "The Jiang–Su algebra revisited". Journal für die Reine und Angewandte Mathematik. 2010 (642). arXiv:0801.2259. doi:10.1515/crelle.2010.039. S2CID 14639268.
• Rørdam, Mikael (2019). "Fixed-points in the cone of traces on a C*-algebra". Transactions of the American Mathematical Society. 371 (12): 8879–8906. doi:10.1090/tran/7797. ISSN 0002-9947.

• Rørdam, M.; Larsen, Flemming; Laustsen, N. J. (2000-07-20). An Introduction to K-Theory for C*-Algebras. ISBN 9780521789448.
• Rørdam, M.; Størmer, Erling (2001-11-20). Classification of Nuclear C*-Algebras. Entropy in Operator Algebras. ISBN 9783540423058.