Date | Time | Room | Title |
---|---|---|---|

Monday, March 28, 2005 |
4:00-5:00 pm | BESC 180 |
Mathematical ImpossibilitiesThis is mainly about the impossibility (within the rules of Greek geometry) of angle trisection. Some other impossibilities - solution of fifth and higher degree equations by a radical formula, the Fermat problem - will be briefly mentioned. This lecture begins with the quadratic formula and should be understandable to anybody with a reasonable high school education. |

Wednesday, March 30, 2005 |
4:00-5:00 pm | ECCR 1B40 |
What is K-Theory and what is it good for?This lecture begins with the definition of K(A) via idempotent matrices, where A is a ring with unit. The basic example of the idempotent matrix which "is" the Möbius band is then explained. Next, the vector fields on spheres problem (which was solved by J.F. Adams using K-theory) is taken up. Finally, the connection of K-theory to the Riemann-Roch problem is briefly indicated. This lecture should be comprehensible to people who are familiar with basic definitions such as ring, abelian group, continuity, matrix multiplication, holomorphic function. |

Friday, April 1, 2005 |
4:00-5:00 pm | ECCR 1B40 |
Trees, Buildings, Symmetric Spaces, and K-Theory for Group C* algebrasThis lecture begins with a list of problems in various parts of mathematics. The point is then made that all of these problems are contained in the Baum-Connes conjecture on the K-theory of group C* algebras. The lecture concludes by stating the relevant problem, and giving some indication of the proposed solution. This lecture should be comprehensible to people with some additional mathematical background to that needed for Lecture II. For example, the definitions of Hilbert space and topological group will be assumed. |

## Paul Baum |
Paul Frank Baum is Evan Pugh Professor of Mathematics at Penn State University. He previously taught at Brown University and Princeton University. He received his undergraduate degree from Harvard College (1958) and his Ph.D. from Princeton University (1963). For the academic year 1958-59 he was an "élève étranger" at the École Normale Supérieure in Paris. His Princeton Ph.D. thesis was written under the direction of John Moore and Norman Steenrod. Professor Baum's work in mathematics has been interdisciplinary, ranging from algebraic geometry to K-theory of operator algebras. In 1980 he began the joint effort with Alain Connes that led to the formulation of the conjecture now known as the Baum-Connes conjecture. This conjecture is unusual in that it cuts across several different areas of mathematics and reveals connections between problems that earlier appeared to be totally unrelated. During 2004 Professor Baum lectured on the Baum-Connes conjecture at universities and research institutes in Europe and the USA. He had visiting appointments at IHES (Institut des Hautes Études Scientifiques) and at IAS (Institute for Advanced Study). He gave the 2004 Kemeny Lectures at Dartmouth College. In 2005 he will give invited lecture series in India (Tata Institute for Fundamental Research), Japan (Keio University), and Poland (Stefan Banach Institute). |

This Lecture Series is funded by an endowment given by Professor Ira M. DeLong, who came to the University of Colorado in 1888 at the age of 33. Professor DeLong essentially became the mathematics department by teaching not only the college subjects but also the preparatory mathematics courses. Professor DeLong was a prominent citizen of the community of Boulder as well as president of the Mercantile Bank and Trust Company, organizer of the Colorado Education Association, and president of the charter convention that gave Boulder the city manager form of government in 1917. After his death in 1942 it was decided that the bequest he made to the mathematics department would accumulate interest until income became available to fund DeLong prizes for undergraduates and DeLong Lectureships to bring outstanding mathematicians to campus each year. The first DeLong Lectures were delivered in the 1962-63 academic year.

1962-1963 Paul Halmos

1963-1964 Marshall Hall Jr.

1964-1965 Edwin Hewitt

1965-1966 George Polya

1966-1967 Alfred Tarski

1967-1968 John Milnor

1968-1969 Paul Cohen

1969-1970 Jurgen Moser

1970-1971 Mark Kac, Irving Kaplansky

1971-1972 Abraham Robinson

1972-1973 George Mackey

1973-1974 Olga Taussky Todd

1974-1975 Andrew Gleason

1975-1976 Tosio Kato

1976-1977 Hugh Montgomery

1977-1978 Elias Stein

1978-1979 Raoul Bott

1979-1980 Alan Weinstein

1980-1981 Enrico Bombieri

1981-1982 Richard S. Varga

1963-1964 Marshall Hall Jr.

1964-1965 Edwin Hewitt

1965-1966 George Polya

1966-1967 Alfred Tarski

1967-1968 John Milnor

1968-1969 Paul Cohen

1969-1970 Jurgen Moser

1970-1971 Mark Kac, Irving Kaplansky

1971-1972 Abraham Robinson

1972-1973 George Mackey

1973-1974 Olga Taussky Todd

1974-1975 Andrew Gleason

1975-1976 Tosio Kato

1976-1977 Hugh Montgomery

1977-1978 Elias Stein

1978-1979 Raoul Bott

1979-1980 Alan Weinstein

1980-1981 Enrico Bombieri

1981-1982 Richard S. Varga

1982-1983 Charles Fefferman

1983-1984 S.S. Chern

1984-1985 Robert Zimmer

1985-1986 Gerd Faltings

1986-1987 Dennis Sullivan

1987-1988 Stephen Smale

1988-1989 Branko Grunbaum

1989-1990 Ronald Graham

1990-1991 Kenneth Ribet

1991-1992 Michael Atiyah

1992-1993 John H. Conway

1993-1994 John Tate

1994-1995 Vladimir Arnold

1996-1997 Alain Connes

1997-1998 Barry Mazur

1999-2000 Nigel Higson

2000-2001 Jeff Cheeger

2001-2002 Vaughan F. R. Jones

2002-2003 Richard Taylor

2003-2004 Phillip A. Griffiths

1983-1984 S.S. Chern

1984-1985 Robert Zimmer

1985-1986 Gerd Faltings

1986-1987 Dennis Sullivan

1987-1988 Stephen Smale

1988-1989 Branko Grunbaum

1989-1990 Ronald Graham

1990-1991 Kenneth Ribet

1991-1992 Michael Atiyah

1992-1993 John H. Conway

1993-1994 John Tate

1994-1995 Vladimir Arnold

1996-1997 Alain Connes

1997-1998 Barry Mazur

1999-2000 Nigel Higson

2000-2001 Jeff Cheeger

2001-2002 Vaughan F. R. Jones

2002-2003 Richard Taylor

2003-2004 Phillip A. Griffiths

2004-2005 Paul Baum

2005-2006 Isadore M. Singer

2006-2007 Sir Roger Penrose

2007-2008 Maxim Kontsevich

2008-2009 Persi Diaconis

2009-2010 Ieke Moerdijk

2010-2011 Endre Szemerédi

2011-2012 Vitaly Bergelson

2012-2013 Yuval Peres

2013-2014 Benedict H. Gross

2014-2015 Robert Bryant

2015-2016 Magdalena Musat

2017-2018 Michael J. Hopkins

2018-2019 Kristin Lauter

2019-2020 Barry Simon

2005-2006 Isadore M. Singer

2006-2007 Sir Roger Penrose

2007-2008 Maxim Kontsevich

2008-2009 Persi Diaconis

2009-2010 Ieke Moerdijk

2010-2011 Endre Szemerédi

2011-2012 Vitaly Bergelson

2012-2013 Yuval Peres

2013-2014 Benedict H. Gross

2014-2015 Robert Bryant

2015-2016 Magdalena Musat

2017-2018 Michael J. Hopkins

2018-2019 Kristin Lauter

2019-2020 Barry Simon

If you have any questions concerning this lecture series, please contact
Mathematics.