Peter Michael Rosenthal (born June 1, 1941) is

Canadian-American Canadian Americans is a term that can be applied to American citizens whose ancestry is wholly or partly Canadian, or citizens of either country that hold dual citizenship. The term ''Canadian'' can mean a nationality or an ethnicity. Canadia ...

Professor Emeritus of Mathematics at the

University of Toronto The University of Toronto (UToronto or U of T) is a public research university in Toronto, Ontario, Canada, located on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution ...

, an adjunct professor of Law at the University of Toronto, and a lawyer in private practice.

Early life

Rosenthal grew up in

Queens Queens is a borough of New York City, coextensive with Queens County, in the U.S. state of New York. Located on Long Island, it is the largest New York City borough by area. It is bordered by the borough of Brooklyn at the western tip of Long ...

, New York with his parents and two brothers.

Mathematics career

Rosenthal graduated from

Queens College, City University of New York Queens College (QC) is a public college in the Queens Boroughs of New York City, borough of New York City. It is part of the City University of New York system. Its 80-acre campus is primarily located in Flushing, Queens. It has a student body ...

with a B.S. in Mathematics in 1962. In 1963 he obtained an MA in Mathematics and in 1967 a Ph.D. in Mathematics from the

University of Michigan , mottoeng = "Arts, Knowledge, Truth" , former_names = Catholepistemiad, or University of Michigania (1817–1821) , budget = $10.3 billion (2021) , endowment = $17 billion (2021)As o ...

; his Ph.D. thesis advisor was

Paul Halmos Paul Richard Halmos ( hu, Halmos Pál; March 3, 1916 – October 2, 2006) was a Hungarian-born American mathematician and statistician who made fundamental advances in the areas of mathematical logic, probability theory, statistics, operator ...

. His thesis, "On lattices of invariant subspaces" concerns operators on

Hilbert space In mathematics, Hilbert spaces (named after David Hilbert) allow generalizing the methods of linear algebra and calculus from (finite-dimensional) Euclidean vector spaces to spaces that may be infinite-dimensional. Hilbert spaces arise natural ...

, and most of his subsequent research has been in operator theory and related fields. Much of his work has been related to the

invariant subspace problem In the field of mathematics known as functional analysis, the invariant subspace problem is a partially unresolved problem asking whether every bounded operator on a complex Banach space sends some non-trivial closed subspace to itself. Many vari ...

, the still-unsolved problem of the existence of invariant subspaces for bounded linear operators on Hilbert space. Among many other topics, he has made substantial contributions to the development of reflexive and reductive operator algebras and to the study of lattices of invariant subspaces, composition operators on the Hardy-Hilbert space and linear operator equations. His publications include many with his long-time collaborator Heydar Radjavi, including the book "Invariant subspaces" (Springer-Verlag, 1973; second edition 2003). Rosenthal has supervised the Ph.D. theses of fifteen students and the research work of a number of post-doctoral fellows.

Legal career

In parallel with his career in mathematics, Rosenthal has pursued a career in law. He worked as a paralegal before obtaining an LL.B. from the

in 1990. He was called to the Ontario Bar in 1992. He is a major figure in the Toronto legal community, and has been profiled by

Toronto Life ''Toronto Life'' is a monthly magazine about entertainment, politics and life in Toronto, Ontario, Canada. ''Toronto Life'' also publishes a number of annual special interest guides about the city, including ''Real Estate'', ''Stylebook'', ''Eatin ...

, ''

The Globe and Mail ''The Globe and Mail'' is a Canadian newspaper printed in five cities in western and central Canada. With a weekly readership of approximately 2 million in 2015, it is Canada's most widely read newspaper on weekdays and Saturdays, although it ...

'', and the

Toronto Star The ''Toronto Star'' is a Canadian English-language broadsheet daily newspaper. The newspaper is the country's largest daily newspaper by circulation. It is owned by Toronto Star Newspapers Limited, a subsidiary of Torstar Corporation and part ...

In 2006, Now Magazine named Rosenthal Toronto's "Best activist lawyer". In May 2016, he was awarded a Law Society Medal by the Law Society of Upper Canada. Rosenthal represented

Miguel Figueroa Miguel Figueroa (born July 29, 1952) is a Canadian political activist who was the leader of the Communist Party of Canada from 1992 to 2015. He is known for the landmark Figueroa case, which redefined the role of small parties and Canadian Parl ...

, the leader of the

Communist Party of Canada The Communist Party of Canada (french: Parti communiste du Canada) is a federal political party in Canada, founded in 1921 under conditions of illegality. Although it does not currently have any parliamentary representation, the party's can ...

, in the case Figueroa v. Canada before the

Supreme Court of Canada The Supreme Court of Canada (SCC; french: Cour suprême du Canada, CSC) is the Supreme court, highest court in the Court system of Canada, judicial system of Canada. It comprises List of Justices of the Supreme Court of Canada, nine justices, wh ...

. The court ruled in Figueroa's favor, striking down a law that prohibited small political parties from obtaining the same tax benefits as large parties. He has represented hundreds of activists who faced charges as a result of political protests, including

Shawn Brant Shawn Brant is a Native activist who lives on the Tyendinaga Mohawk Territory, Ontario, Canada. He has been involved in direct action struggles for Native land rights, in conflict with Ontario provincial authorities. In the 1990s, Brant particip ...

John Clarke (activist) John Clarke is an anti-poverty activist who lives in Toronto, Ontario, Canada. As of 2019, he was teaching at York University. Activism A native of United Kingdom, Britain, he moved to Toronto, Ontario and became an organizer there.Keenan Kusan ...

, Vicki Monague of Stop Dump Site 41 ,

Dudley Laws Dudley Laws (May 7, 1934March 24, 2011) was a Canadian civil rights activist and executive director of the Black Action Defence Committee. Laws was born in Saint Thomas Parish, Jamaica, to parents Ezekiel and Agatha Laws, and was a brother to six ...

and Jaggi Singh, and has written articles about some of those cases.

Works

* , 2nd edition * * * (with

Sheldon Axler Sheldon Jay Axler (born November 6, 1949, Philadelphia) is an American mathematician and textbook author. He is a professor of mathematics and the Dean of the College of Science and Engineering at San Francisco State University. He graduated fr ...

and Donald Sarason) editors
''A Glimpse at Hilbert Space Operators''

Birkhäuser Birkhäuser was a Swiss publisher founded in 1879 by Emil Birkhäuser. It was acquired by Springer Science+Business Media in 1985. Today it is an imprint used by two companies in unrelated fields: * Springer continues to publish science (particu ...

, 2010. *

References

{{DEFAULTSORT:Rosenthal, Peter 1941 births Living people University of Michigan alumni University of Toronto alumni University of Toronto faculty University of Toronto Faculty of Law faculty Canadian mathematicians 20th-century Canadian mathematicians Queens College, City University of New York alumni Canadian lawyers Operator theorists Algebraists People from Queens, New York