Operator Theory Seminar
The Operator Theory Seminar at IUPUI has met regularly since January 2007.
This page is a record, in reverse chronological order, of the topics and speakers that have been included.
End of Fall Semester 2017
FALL 2017
November 29
Michael Pilla, (IUPUI)
Classifying Linear Fractional Maps on the Unit Ball in C^2, (cont'd)
November 15
Michael Pilla, (IUPUI)
Classifying Linear Fractional Maps on the Unit Ball in C^2
November 1
Jim Carter and Bill Johnston, (Butler U.)
Buckholtz's Work on Hilbert Space Projections
October 25
Carl Cowen, (IUPUI)
Buckholtz's Work on Hilbert Space Projections
October 18
Carl Cowen, (IUPUI)
Hyponormality of Toeplitz Operators (cont'd)
October 11
Carl Cowen, (IUPUI)
Hyponormality of Toeplitz Operators (cont'd)
October 4
Carl Cowen, (IUPUI)
Hyponormality of Toeplitz Operators (cont'd)
September 27
Carl Cowen, (IUPUI)
Hyponormality of Toeplitz Operators (cont'd)
September 20
Carl Cowen, (IUPUI)
Hyponormality of Toeplitz Operators (cont'd)
September 13
Carl Cowen, (IUPUI)
Hyponormality of Toeplitz Operators (cont'd)
September 6
Carl Cowen, (IUPUI)
Hyponormality of Toeplitz Operators
August 30
Bill Higdon
Weighted composition operators and multiplier spaces
End of Spring Semester 2017
SPRING 2017
April 19
Rebecca Wahl (Butler University)
Operators Commuting with Nilpotent Matrices
March 22
Carl Cowen (IUPUI)
Dynamics and Fixed Points for Analytic Functions on the Unit Disk
February 1
Bill Johnston (Butler University)
Commutants, Kernels, and Invariant Subspaces of Matrices, Redux
January 25
Carl Cowen (IUPUI)
A Hyperbolic Universal Operator Commuting with a Compact Operator (cont'd)
January 18
Carl Cowen (IUPUI)
A Hyperbolic Universal Operator Commuting with a Compact Operator
End of Fall Semester 2016
FALL 2016
November 2
Scott Kaschner (Butler University)
Dynamical Degrees and the Projective Heat Map Acting on Pentagons (cont'd)
October 26
Scott Kaschner (Butler University)
Dynamical Degrees and the Projective Heat Map Acting on Pentagons
October 19
John Herr (Butler University)
Fourier Series for Singular Measures and the Kaczmarz Algorithm (cont'd)
October 5
John Herr (Butler University)
Fourier Series for Singular Measures and the Kaczmarz Algorithm (cont'd)
September 28
John Herr (Butler University)
Fourier Series for Singular Measures and the Kaczmarz Algorithm (cont'd)
September 21
John Herr (Butler University)
Fourier Series for Singular Measures and the Kaczmarz Algorithm (cont'd)
September 14
John Herr (Butler University)
Fourier Series for Singular Measures and the Kaczmarz Algorithm
September 7
Carl Cowen (IUPUI)
Redundant Matrices for Representing Linear Transformations
August 31
Sivaram Narayan (Central Michigan University
From Bases to Frames: An Introduction to the Theory of Frames
End of Spring Semester 2016
SPRING 2016
April 20
Carl Cowen (IUPUI)
Brittney Miller's Work on Kernels of Adjoints of Composition Operators
April 13
Bill Higdon
A Refinement of Our Numerical Range Theorem
March 23
Derek Thompson (Taylor University)
Complex Symmetric Composition Operators on H^2
March 2
Bill Johnston (Butler University)
Tom Kriete's L^2(d mu) Representation of the Invariant Subspaces of the H^2 Backward Shift Operator
February 24
Edward Timko (Indiana U, Bloomington)
Commuting Isometries Satisfying a Class of Polynomial Equations (cont'd)
February 17
Edward Timko (Indiana U, Bloomington)
Commuting Isometries Satisfying a Class of Polynomial Equations
January 27
Bill Johnston (Butler University)
S-Inner Operators and Invariant Subspaces
End of Fall Semester 2015
FALL 2015
December 2
Bill Johnston (Butler University)
Matrix Invariant Subspace Construction -- Additional Progress (cont'd)
November 18
Bill Johnston (Butler University)
Matrix Invariant Subspace Construction -- Additional Progress
October 28
Bill Higdon
Two New Results for Composition Operators Induced by Parabolic Mappings of Non-automorphism Type
October 21
Rebecca Wahl (Butler University)
A New Result in the Search for a Proof of the Invariant Subspace Theorem (cont'd)
October 7
Carl Cowen (IUPUI)
A New Result in the Search for a Proof of the Invariant Subspace Theorem (cont'd)
September 30
Carl Cowen (IUPUI)
A New Result in the Search for a Proof of the Invariant Subspace Theorem (cont'd)
September 23
Carl Cowen (IUPUI)
A New Result in the Search for a Proof of the Invariant Subspace Theorem
September 16
Carl Cowen (IUPUI)
The Berezin Range of a Composition Operator with Automorphic Symbol (cont'd)
September 9
Chris Felder (Butler & IUPUI) and Carl Cowen (IUPUI)
The Berezin Range of a Composition Operator with Automorphic Symbol (cont'd)
September 2
Chris Felder (Butler & IUPUI) and Carl Cowen (IUPUI)
The Berezin Range of a Composition Operator with Automorphic Symbol
End of Spring Semester 2015
SPRING 2015
April 22
Bill Johnston (Butler University)
Rosenblum's Diagonalization of Some Hankel Matrices
April 8
Bill Higdon
Vieta's Formulas and Symmetric Polynomials
April 1
Derek Thompson (Trine University)
Hyponormal Weighted Composition Operators on H^2, the Hardy Hilbert Space
March 11
Carl Cowen (IUPUI)
The Numerical Range of Matrices: Can We Understand Kippenhahn's Algebraic Geometry? (cont'd)
March 4
Carl Cowen (IUPUI)
The Numerical Range of Matrices: Can We Understand Kippenhahn's Algebraic Geometry? (cont'd)
February 25
Carl Cowen (IUPUI)
The Numerical Range of Matrices: Can We Understand Kippenhahn's Algebraic Geometry?
February 18
Carl Cowen (IUPUI)
Rosenblum's Paper: On the Operator Equation XB - XA = Q
February 11
Carl Cowen (IUPUI)
Commutants and the Operator Equation AX=sXA (cont'd)
February 4
Carl Cowen (IUPUI)
Commutants and the Operator Equation AX=sXA
End of Fall Semester 2014
FALL 2014
December 3
Bill Johnston (Butler University)
Kernels of Commuting Matrices (cont'd)
November 19
Bill Johnston (Butler University)
Kernels of Commuting Matrices
November 12
Carl Cowen (IUPUI)
Applications of Covering Maps in Complex Analysis and Operator Theory
November 5
Eva Gallardo Gutierrez (Universidad Complutense de Madrid)
An Extension of a Theorem of Domar on Invariant Subspaces
October 29
Carl Cowen (IUPUI)
Intro to Work of Domar on Shifts and Invariant Subspaces
October 8
Slawek Klimek (IUPUI)
A Quantum Pair of Pants (cont'd)
October 1
Slawek Klimek (IUPUI)
A Quantum Pair of Pants
September 24
Brittney Miller (Purdue U, West Lafayette)
Adjoints of Rationally Induced Composition Operators on the Bergman Space (cont'd)
September 17
Brittney Miller (Purdue U, West Lafayette)
Adjoints of Rationally Induced Composition Operators on the Bergman Space
September 10
Carl Cowen (IUPUI)
Sophomoric Matrix Multiplication and Applications to Operator Theory (cont'd)
September 3
Carl Cowen (IUPUI)
Sophomoric Matrix Multiplication and Applications to Operator Theory
End of Spring Semester 2014
SPRING 2014
April 2
Bill Johnston (Butler University)
Commutants for n by n Matrices
March 5
Samuel Roth (IUPUI)
A Proof of von Neumann's Ergodic Theorem and Its Application to Obtain a Beautiful Theorem in Dynamical Systems
February 26
Carl Cowen (IUPUI)
A Novel Basis for H^2 and a Conjecture
February 12
John Clifford (University of Michigan, Dearborn)
Invertible Composition Operators: The Product of a Composition Operator with the Adjoint of a Composition Operator
January 29
Bill Higdon (University of Indianapolis)
The Numerical Range Of Some Weighted Composition Operators (cont'd)
January 22
Bill Higdon (University of Indianapolis)
The Numerical Range Of Some Weighted Composition Operators
End of Fall Semester 2013
FALL 2013
December 4
Derek Thompson (Trine University)
Spectra of Weighted Composition Operators
November 20
Bill Johnston (Butler University)
The Hardy Space H^2 as a Duhamel Algebra (cont'd)
November 13
Bill Johnston (Butler University)
The Hardy Space H^2 as a Duhamel Algebra ('74 and '75 work of Wigley)
November 6
Samuel Roth (IUPUI)
Summable Eigenvectors of Infinite Matrices and Some Applications in Dynamics (cont'd)
October 30
Samuel Roth (IUPUI)
Summable Eigenvectors of Infinite Matrices and Some Applications in Dynamics
October 23
Carl Cowen (IUPUI)
Invariant Subspaces for Operators on Finite Dimensional Spaces: work of Gohberg, Lancaster, and Rodman
October 16
Carl Cowen (IUPUI)
New Results on Spectra of Composition Operators in the Plane Translation Case: work of Paul Bourdon
September 25
Carl Cowen (IUPUI)
Recent Work on the Invariant Subspace Problem (cont'd) (joint work with Eva Gallardo)
September 18
Carl Cowen (IUPUI)
Recent Work on the Invariant Subspace Problem (cont'd) (joint work with Eva Gallardo)
September 11
Carl Cowen (IUPUI)
Recent Work on the Invariant Subspace Problem (cont'd) (joint work with Eva Gallardo)
September 4
Carl Cowen (IUPUI)
Recent Work on the Invariant Subspace Problem (joint work with Eva Gallardo)
SPRING 2013
End of Spring Semester 2013
SPRING 2013
April 24
Bill Johnston (Butler University)
More on Blaschke Products
March 6
Scott Kaschner (IUPUI)
Co-dimension 1 Bottcher Functions (cont'd)
February 27
Scott Kaschner (IUPUI)
Co-dimension 1 Bottcher Functions
February 20
Rebecca Wahl (Butler University)
Geometric Properties of Finite Blaschke Products (cont'd)
February 13
Rebecca Wahl (Butler University)
Geometric Properties of Finite Blaschke Products (cont'd)
February 6
Rebecca Wahl (Butler University)
Geometric Properties of Finite Blaschke Products
FALL 2012
End of Fall Semester 2012
FALL 2012
December 13 (Thursday!) in SL 165 (Special Room!) 10:30a (Special Time!)
Special Seminar with Modern Analysis & Geometry
Carl Cowen, (IUPUI)
How I Spent My Sabbatical: Rota's Universal Operators and Invariant Subspaces in Hilbert Spaces
(joint work with Eva Gallardo Gutierrez, Univ. Complutense de Madrid)
December 5
Jim Carter, (IUPUI)
Thomson's work (mid 1970's) on Commutants of Analytic Toeplitz Operators, (con'td)
November 28
Jim Carter, (IUPUI)
Thomson's work (mid 1970's) on Commutants of Analytic Toeplitz Operators
November 21
Thanksgiving Break!!
November 14
Erin Rizzie (Purdue U, WL)
Cowen's 1974 Paper on Finite Blaschke Products as Compositions of Other Blaschke Products (cont'd)
November 7
Erin Rizzie (Purdue U, WL)
Cowen's 1974 Paper on Finite Blaschke Products as Compositions of Other Blaschke Products (cont'd)
October 31
Rebecca Wahl (Butler U.)
Cowen's 1974 Paper on Finite Blaschke Products as Compositions of Other Blaschke Products (cont'd)
October 24
Derek Thompson (IUPUI)
Invariant Subspaces for Composition Operators (cont'd)
October 17
Rebecca Wahl (Butler U.)
Cowen's 1974 Paper on Finite Blaschke Products as Compositions of Other Blaschke Products
October 10
No Meeting This Week!
October 3
Carl Cowen (IUPUI)
Minimal Vectors and Their Application to the Invariant Subspace Problem
September 26
Derek Thompson (IUPUI)
Invariant Subspaces for Composition Operators (cont'd)
September 19
Derek Thompson (IUPUI)
Invariant Subspaces for Composition Operators (cont'd)
September 12
Derek Thompson (IUPUI)
Invariant Subspaces for Composition Operators
September 5
Bill Johnston (Butler Univ)
Another Proof that the Hermite Functions Span L^2(R)
August 29
Organizational Meeting!
SPRING 2012
End of Spring Semester 2012
SPRING 2012
April 25
Carl Cowen (IUPUI)
Projections Commuting with Blaschke Toeplitz Operators (joint work with Rebecca Wahl) (conclusion)
April 18
No Meeting Today!
April 11
Carl Cowen (IUPUI)
Projections Commuting with Blaschke Toeplitz Operators (joint work with Rebecca Wahl) (cont'd)
April 4
Carl Cowen (IUPUI)
Projections Commuting with Blaschke Toeplitz Operators (joint work with Rebecca Wahl)
March 28
No Meeting Today!
March 21
Rebecca Wahl (Butler)
Deddens and Wong's work on Commutants of Inner Function Toeplitz Operators
March 14
No Meeting! SPRING BREAK!
March 7
Carl Cowen (IUPUI)
An Old Look at Commutants (joint work with Rebecca Wahl)
February 29
No Meeting!
February 22
No Meeting!
February 15
Jim Carter (IUPUI)
Composition Operators on the Newton Space (Work of MacDonald and Rosenthal) (concluded)
February 8
Jim Carter (IUPUI)
Composition Operators on the Newton Space (Work of MacDonald and Rosenthal) (cont'd)
February 1
Jim Carter (IUPUI)
Composition Operators on the Newton Space (Work of MacDonald and Rosenthal) (cont'd)
January 25
Jim Carter (IUPUI)
Composition Operators on the Newton Space (Work of MacDonald and Rosenthal)
January 18
Carl Cowen (IUPUI)
The Point Spectrum of Weighted Composition Operators
FALL 2011
End of Fall Semester 2011
FALL 2011
December 7
Jim Carter, Derek Thompson (IUPUI)
Commutants of composition operators on the Hardy Hilbert space and Restrictions to invariant subspaces of composition operators
November 30
Carl Cowen (IUPUI)
Reducing subspaces for analytic multiplication operators on the Bergman space; work of Douglas, Putinar, and Wang
November 23
No Meeting Today
November 16
Bill Johnston (Butler University)
Orthogonal Bases for L^2 Spaces: Adopting an Elementary Proof
Technique of Wheeden and Zygmund
November 9
Carl Cowen (IUPUI)
Montes' Work on Invariant Subspace Lattice for Composition Operators; Part 7: Conclusion(!)
November 2
Carl Cowen (IUPUI)
Title: Montes' Work on Invariant Subspace Lattice for Composition Operators;
Part 6: Use of the Sobolev Embedding Theorem
October 26
Carl Cowen (IUPUI)
Montes' Work on Invariant Subspace Lattice for Composition Operators; Part 5: Even More on the Main Equivalence
October 19
NO SEMINAR
October 12
Carl Cowen (IUPUI)
Montes' Work on Invariant Subspace Lattice for Composition Operators; Part 4: More on the Main Equivalence
October 5
Carl Cowen (IUPUI)
Montes' Work on Invariant Subspace Lattice for Composition Operators; Part 3: The Main Equivalence
September 28
Carl Cowen (IUPUI)
Montes' Work on Invariant Subspace Lattice for Composition Operators; Part 2: Banach Algebra Theorem
September 21
Carl Cowen (IUPUI)
Montes' Work on Invariant Subspace Lattice for Composition Operators; Part 1: Banach Algebra Theorem
work of Montes-Rodriguez, Ponce-Escudero, and Shkarin
September 14
Carl Cowen (IUPUI)
Norm Inequalities through the Magic of Schur Products (concluded)
September 7
Carl Cowen (IUPUI)
Norm Inequalities through the Magic of Schur Products (cont'd)
August 31
Carl Cowen (IUPUI)
Norm Inequalities through the Magic of Schur Products
work of C. Hammond and L. J. Patton
SPRING 2011
End of Spring Semester 2011
April 27
Carl Cowen (IUPUI)
Commutants of Analytic Toeplitz Operators (cont'd)
April 20
Bobby Bridges (Purdue, West Lafayette)
A Solution of Schroeder's Equation in Several Variables
April 13
Carl Cowen (IUPUI)
Commutants of Analytic Toeplitz Operators
April 6
Carl Cowen (IUPUI)
"Norms of Composition Operators with Rational Symbol" by Jonathan Shapiro, et. al. Revisited
March 30
Bill Higdon (University of Indianapolis)
Model for Iteration of Analytic Maps of the Disk to Itself (cont'd)
March 23
Bill Higdon (University of Indianapolis)
Model for Iteration of Analytic Maps of the Disk to Itself
March 16
NO MEETING: IUPUI Spring Break
March 9
Carl Cowen (IUPUI)
On Norm Attaining Operators
March 2
Carl Cowen (IUPUI)
On Semi-groups
February 23
Derek Thompson (IUPUI)
"Norms of Composition Operators with Rational Symbol" by Jonathan Shapiro, et. al.
February 16
Roland Roeder (IUPUI)
Two Papers of Borcea and Branden on "Linear Operators Preserving Stability" (concluded)
February 9
Roland Roeder (IUPUI)
Two Papers of Borcea and Branden on "Linear Operators Preserving Stability" (cont'd)
February 2
ICE! No Seminar!
January 26
Roland Roeder (IUPUI)
Two Papers of Borcea and Branden on "Linear Operators Preserving Stability" (cont'd)
January 19
Roland Roeder (IUPUI)
Two Papers of Borcea and Branden on "Linear Operators Preserving Stability"
Borcea and Branden I Borcea and Branden II
FALL 2010
End of Fall Semester 2010
Seminar cancelled (illness)
November 10
Carl Cowen (IUPUI)
Discussion on an intertwining problem
November 3
Becky Wahl (Butler University)
Mahvidi on "Invariant Subspaces of Composition Operators " (cont'd)
October 27
Becky Wahl (Butler University)
Mahvidi on "Invariant Subspaces of Composition Operators " (cont'd)
October 27
Becky Wahl (Butler University)
Mahvidi on "Invariant Subspaces of Composition Operators"
Becky Wahl's notes on Mahvidi's paper
October 20
Becky Wahl (Butler University)
Vukotic, et al., on "Uniformly Discrete Sequences..."
October 13
Carl Cowen (IUPUI)
Unitary Operators Carrying Given Subspaces to Other Given Su bspaces (concluded)
October 6
Carl Cowen (IUPUI)
Unitary Operators Carrying Given Subspaces to Other Given Su bspaces (cont'd)
September 29
Carl Cowen (IUPUI)
Unitary Operators Carrying Given Subspaces to Other Given Su bspaces (cont'd)
September 22
Carl Cowen (IUPUI)
Unitary Operators Carrying Given Subspaces to Other Given Subspaces (cont'd)
September 15
Carl Cowen (IUPUI)
Unitary Operators Carrying Given Subspaces to Other Given Subspaces (cont'd)
September 8
Carl Cowen (IUPUI)
Unitary Operators Carrying Given Subspaces to Other Given Subspaces
SPRING 2010
End of Spring Semester 2010
April 14
Carl Cowen (IUPUI)
Bottcher's Functional Equation: the fifth case for models for analytic functions mapping the disk to itself (cont'd)
April 7
seminar postponed
March 31
No Meeting
March 24
Carl Cowen (IUPUI)
Bottcher's Functional Equation: the fifth case for models for analytic functions mapping the disk to itself
Bottcher's Equation paperMarch 17
No Meeting
March 10
No Meeting
March 3
No Meeting
February 24
No Meeting
February 10
No Meeting
February 3
Alberto Condori (Rose-Hulman Institute of Technology)
Hankel Operators and Meromorphic Approximation
January 27
Carl Cowen (IUPUI)
What Are the Pseudospectra of an Operator?
January 20
William Higdon (University of Indianapolis)
On Bourdon and Shapiro's "Intertwining relations and extended eigenvalues for analytic Toeplitz operators"
FALL 2009
End of Fall Semester 2009
December 2
Sivaram Narayan (Central Michigan University)
"Commutators of Weighted Composition Operators"
November 25
Thanksgiving break, no meeting
November 18
Sivaram Narayan (Central Michigan University)
"Compact Weighted Composition Operators"
November 11
Sivaram Narayan (Central Michigan University)
"Normal Weighted Composition Operators"
November 11
Sivaram Narayan (Central Michigan University)
"Normal Weighted Composition Operators"
November 4
Carl Cowen (IUPUI)
"Discussion: problems in functional analysis"
October 21
Carl Cowen (IUPUI)
"Unitary Equivalence of One-parameter Groups of Toeplitz and Composition Operators"
October 14
No Meeting Today
October 7
Maria Neophytou (Purdue University, West Lafayette)
"Spectra of Some Composition Operators" (cont'd)
September 30
Maria Neophytou (Purdue University, West Lafayette)
"Spectra of Some Composition Operators" (cont'd)
September 23
No Meeting Today
September 16
Carl Cowen (IUPUI)
"Spectra of Some Composition Operators"
September 9
Carl Cowen (IUPUI)
First Meeting of Fall Semester
"Essentially Linear Fractional Maps of the Disk into Itself"
SPRING 2009
End of Spring Semester 2009
Carl Cowen (IUPUI)
Stephan Garcia's Work on Complex Symmetric Operators (cont'd)
March 25
Carl Cowen (IUPUI)
Stephan Garcia's Work on Complex Symmetric Operators
March 18
No Meeting (IUPUI Spring Break)
March 11 (Seminar will start at 3:00p today)
Michael Jury (University of Florida)
Valiron's Theorem on the Unit Ball
March 4
Carl Cowen (IUPUI)
Integration on spheres
February 25
NO MEETING (IUPUI)
February 18
Carl Cowen (IUPUI)
Integration on spheres
February 11
Carl Cowen (IUPUI)
Integration on spheres
February 4
Eva Gallardo-Gutierrez (University of Zaragoza, Spain)
replaced by Carl Cowen (IUPUI)
Discussion on "On the path component of compact composition operators in the Hardy space (conclusion)"
January 28 Campus Closed; seminar postponed as above
January 28
Eva Gallardo-Gutierrez (University of Zaragoza, Spain)
On the path component of compact composition operators in the Hardy space (conclusion)
January 21
Eva Gallardo-Gutierrez (University of Zaragoza, Spain)
On the path component of compact composition operators in the Hardy space
January 14 (First meeting of the semester)
Carl Cowen (IUPUI)
Integrals related to H^2(B^N)
FALL 2008
End of Fall Semester 2008
Spring 2011 Fall 2010 Spring 2010 Fall 2009 Spring 2009 Spring 2008Discussion on problems in Operator Theory
November 12
Morteza Seddighin (IU East)
Anti-eigenvalues and Operator Inequalities
Abstract
The Kantrovich inequality and Kantrovich-like inequalities for positive bounded operators have had many applications in operator theory, and other areas since 1948. The concept of Antieigenvalue or the operator cosine was independently introduced in 1967 by Karl Gustafson for use in perturbation of semigroup generators. For a positive operator, both the Kantorovich inequality and the value of operator cosine are expressed in terms to the smallest and largest eigenvalues of the operator, and it turns out that the former is obtained from the latter. We will discuss the extensions of Kantorovich inequality and Antieigenvalue to other classes of operators.
November 5
Carl Cowen (IUPUI)
Maps of the unit ball in the Schur-Agler Class (cont'd)
October 29
Carl Cowen (IUPUI)
Maps of the unit ball in the Schur-Agler Class (cont'd)
October 22
Carl Cowen (IUPUI)
Maps of the unit ball in the Schur-Agler Class (cont'd)
October 15
Carl Cowen (IUPUI)
Maps of the unit ball in the Schur-Agler Class (cont'd)
October 8
Carl Cowen (IUPUI)
Maps of the unit ball in the Schur-Agler Class (cont'd)
October 1
Carl Cowen (IUPUI)
Maps of the unit ball in the Schur-Agler Class
September 24
Carl Cowen (IUPUI)
A class of analytic maps of the unit ball in C^N into itself
September 17
Carl Cowen (IUPUI)
Hermitian Weighted Composition Operators on Weighted Hardy Spaces (cont'd)
September 10
Carl Cowen (IUPUI)
Hermitian Weighted Composition Operators on Weighted Hardy Spaces (cont'd)
September 3
Carl Cowen (IUPUI)
Hermitian Weighted Composition Operators on Weighted Hardy Spaces
SPRING 2008
End of Spring Semester 2008
Spring 2011 Fall 2010 Spring 2010 Fall 2009 Spring 2009 Fall 2008April 23
Carl Cowen (IUPUI)
Linear Fractional Maps in C^N and their Composition Operators (cont'd)
April 16
Carl Cowen (IUPUI)
Linear Fractional Maps in C^N and their Composition Operators (cont'd)
April 9
Carl Cowen (IUPUI)
Linear Fractional Maps in C^N and their Composition Operators (cont'd)
April 2
Carl Cowen (IUPUI)
Linear Fractional Maps in C^N and their Composition Operators (cont'd)
March 26
Carl Cowen (IUPUI)
Linear Fractional Maps in C^N and their Composition Operators (cont'd)
March 19
Carl Cowen (IUPUI)
Linear Fractional Maps in C^N and their Composition Operators
March 12
NO MEETING -- Spring Break!
March 5
Discussion
February 27
Discussion
February 20
William Higdon (University of Indianapolis)
Composition Operators Induced by Parabolic Linear Fractional Self-Maps of the Disk (cont'd)
February 13
William Higdon (University of Indianapolis)
Composition Operators Induced by Parabolic Linear Fractional Self-Maps of the Disk
February 6
Carl Cowen (IUPUI)
Invariant subspaces for multiplication operators (concluded)
January 30
Carl Cowen (IUPUI)
Invariant subspaces for multiplication operators
January 23
Carl Cowen (IUPUI)
Invariant subspaces for multiplication operators The subject begins with the
invariant subspaces of a diagonal operator (i.e. a normal operator),
but quickly becomes quite complicated and intricate. The goal of this
series of talks will be to summarize, with few proofs, a recent long
paper by Aleman, Feldman, and Ross on the invariant subspaces of the
operator of multiplication (on the Hardy space) by the Riemann map
of the disk onto a slit disk. The talks will begin with the
ideas from the simpler settings first.
FALL 2007
End of Fall Semester 2007
December 5
Conversation about Numerical Range and Composition Operators
Final Meeting of Fall Semester
November 28
Conversation about Numerical Range and Composition Operators
November 21
No Meeting: Thanksgiving Recess
November 14
Rebecca Wahl (Butler Univ.)
Invariant Subspaces for a Class of Composition Operators
November 7
Bill Higdon (Univ. of Indianapolis)
Toeplitz-Hausdorff Theorem: the Numerical Range Is Convex
October 31
Bill Higdon (Univ. of Indianapolis)
J. H. Shapiro's Notes on the Numerical Range (cont'd)
October 24
Carl Cowen (IUPUI)
October 17
Bill Higdon (Univ. of Indianapolis)
J. H. Shapiro's Notes on the Numerical Range
October 10
Continuation of Discussion on uses of Halmos's Problem on Multiplication Operators
October 3
Continuation of Discussion on uses of Halmos's Problem on Multiplication Operators
September 26
Continuation of Discussion on uses of Halmos's Problem on Multiplication Operators
September 19
Discussion on uses of Halmos's Problem on Multiplication Operators
September 12
Prof. Alfonso Montes-Rodriguez (Univ. of Seville, Spain)
The Lattice of Parabolic Non-automorphism Composition Operators on the Hardy Space
September 5
Carl Cowen (IUPUI)
Adjoints of Composition Operators with Rational Symbol (cont'd)
August 29
Carl Cowen (IUPUI)
Adjoints of Composition Operators with Rational Symbol
SPRING/SUMMER 2007
End of Summer 2007
Spring 2011 Fall 2010 Spring 2010 Fall 2009 Spring 2009 Fall 2008July 18
Hermitian Weighted Composition Operators on H^2 (Part II, reprise)
July 11
Carl Cowen (IUPUI)
Hermitian Weighted Composition Operators on H^2 (Part II)
June 27
Carl Cowen (IUPUI)
Hermitian Weighted Composition Operators on H^2
June 20
William Higdon (Univ. of Indianapolis)
Ugur Gul's Work on Spectral Theory of Composition Operators on Hardy Spaces
End of Spring Semester 2007
Spring 2011 Fall 2010 Spring 2010 Fall 2009 Spring 2009 Fall 2008May 9
Carl Cowen (IUPUI)
Adjoints of Composition Operators on the Hardy Hilbert Space: the Rational Function Case, Part IV
April 18
Carl Cowen (IUPUI)
Adjoints of Composition Operators on the Hardy Hilbert Space: the Rational Function Case, Part III
April 11
Carl Cowen (IUPUI)
Adjoints of Composition Operators on the Hardy Hilbert Space: the Rational Function Case, Part II
April 4
Carl Cowen (IUPUI)
Adjoints of Composition Operators on the Hardy Hilbert Space: the Rational Function Case, Part I
March 28
Carl Cowen (IUPUI)
Adjoints of Composition Operators on the Hardy Hilbert Space: the Linear Fractional Case
March 21
Rebecca Wahl (Butler University)
The Weighted Shift Analogy for C*_phi and Spectral Information: phi(z)=z^2/(2-z) (cont'd)
March 7
Rebecca Wahl (Butler University)
The Weighted Shift Analogy for C*_phi and Spectral Information: phi(z)=z^2/(2-z)
February 28
Carl Cowen (IUPUI)
Introduction to iteration sequences of analytic maps of the disk and to the work of Poggi-Corradini (cont'd)
February 21
Carl Cowen (IUPUI)
Introduction to iteration sequences of analytic maps of the disk and to the work of Poggi-Corradini (cont'd)
February 7
Carl Cowen (IUPUI)
Introduction to iteration sequences of analytic maps of the disk and to the work of Poggi-Corradini (cont'd)
January 31
Carl Cowen (IUPUI)
Introduction to iteration sequences of analytic maps of the disk and to the work of Poggi-Corradini
January 24
Bill Higdon (University of Indianapolis)
The Spectra of Composition Operators from Linear Fractional Maps Acting upon the Dirichlet Space
January 17
Carl Cowen (IUPUI)
Organizational Meeting
Beginning of Seminar