NebraskaIowa IowaNebraska Functional Analysis Seminar
General Format
This is a oneday mathematics conference held once or twice a year, usually in
April and October in Des Moines, Iowa.
The format consists of four hourlong talks, with a oneandahalf or two hour lunch.
between the 2nd and 3rd talk.
The first talk typically starts at 11:00 am and the last talk finishes about 5:00 pm.
We usually meet at
The University of Iowa John and Mary Pappajohn Education Center, located at
1200 Grand Ave., Des Moines, IA 50309.
Here is a map.
The conference first met in March of 1994; the April 2014 meeting represented the
twentieth year and the twentyseventh meeting. (There have not been two meetings every year.)
It is jointly organized by the Mathematics Departments of
Creighton University,
Iowa State University,
The University of Iowa, and
The University of NebraskaLincoln.
Faculty and students from a number of other nearby universities also attend.
All are welcome. There is no registration fee.
If you have any questions, please contact one of the organizers.
Organizers
 Randall Crist of Creighton
 Raul Curto of Iowa
 Yiu T Poon of Iowa State
 Allan Donsig of NebraskaLincoln
Next Meeting: April 8, 2017 in Omaha, Nebraska
 Roger Smith (of Texas A&M University)
 Title: A Galois Correspondence for Crossed Products
 Abstract:
If a discrete group G acts on an operator algebra A (C^{*} or von Neumann) the question arises of
whether the algebras between A and its crossed product by G can be characterized by subgroups of
G. When A is a simple C^{*}algebra and G acts by outer automorphisms, a positive answer has been
given by LandstadOlesenPedersen when G is abelian, by Choda (with some rather restrictive
extra hypotheses) and by Izumi when G is finite. In this talk I will give a positive solution for all
discrete groups G and discuss some consequences. This is joint work with Jan Cameron.
 Daniel Freeman (of St. Louis University)
 Title: The Discretization Problem for Continuous Frames
 Abstract:
Functions on L^{2}([0, 1]) can be analyzed continuously through the Fourier transform, or discretely
through Fourier series and sampling the Fourier transform only at the integers. The discretization
problem essentially asks what other continuous representations can be sampled to obtain
discrete representations. We solve this problem by giving a complete characterization of when
a continuous frame for a Hilbert space may be sampled to obtain a discrete frame. In particular,
every bounded continuous frame may be sampled to obtain a discrete frame. This is joint work
with Darrin Speegle.
 Gabriel Nagy (of Kansas State University)
 Title: Essential inclusions revisited  preliminary report
 Abstract:
Call a C^{*}algebra inclusion A ⊂ B essential, if there is no nontrivial closed two sided ideal
J ⊂ B, such that J ∩ A is empty. Over the past five years or so (joint works with Brown, Reznikoff,
Sims and Williams), most examples of such inclusions were produced by investigating the space
of states on A that extend uniquely to states on B. I will try to explain why conceptually (but not
literally!), this is the only technique that works, if it is suitably adapted to the case when the above
mentioned state space is rather small (or even empty!). As an application, we provide a simplicity
criterion for reduced C^{*}algebras of etale groupoids. (Joint work with Danny Crytser)
 Lance Nielsen (of Creighton University)
 Title: Feynman's Operational Calculus: Introduction and Essential Properties
 Abstract:
After some background and history related to Feynman’s development of his operational calculus,
the JefferiesJohnson approach to the operational calculus will be introduced. We will then
survey some important results and applications of the operational calculus, including a look at
stability properties as well as evolution/generalized integral equations satisfied by the operational
calculus.
NOTE: We will be meeting in Omaha, on the campus of Creighton University, in the HixsonLied Science Building, Room 522.
(campus map).
The conference will start at 1pm and finish by 5pm or so.
There will be a dinner afterwards.
Detailed driving directions: Off I80, take I480 North. Go about 3 miles and take the exit onto Hwy 75 North. Take the first exit off Hwy 75 onto Cumming St. Turn right at the lights onto Cumming St. (now heading east). Head east about 0.3 miles to 24th ST. Turn right on 24th St. (now heading south). Take the next right onto Burt St. (heading west). Drive about 0.10.2 miles and find street parking or park in the lot north of Burt. We will be meeting in the Eppley Bldg. Eppley is south of Burt, visible from the street, and labeled in large letters. Meeting will be on the 3rd floor in Room 309.
Speakers and Titles from Previous Meetings
 November 5, 2016
 Gordon Aiello (of University of Iowa)
 Title: Euclidean Scattering and the Problem of Moments
(slides)
 Calvin Hotchkiss (of Iowa State University)
 Title: Fourier Bases on the ”Skewed Sierpinski Gasket”
(slides)
 Paul Muhly (of University of Iowa)
 Title: Operator Algebras as Algebras of Functions
(slides)
 Abstract:
Suppose R and S are two unital rings and let X be the space of all unital homomorphisms of R to S.
Of course, X may be empty, but under favorable conditions, X can be rich and then R can be represented as a ring of Svalued functions on X: r → r , where r (φ) := φ(r), φ ∈ X.
One can then turn her attention to studying the functions and investigating information they reveal about R.
This may sound familiar – perhaps as some sort of generalized Gelfand theory. In a sense, it is. However, the first thing I want to do is to show that Gelfand was nearly 60 years late to the party. This point of view arose long before Gelfand. I then want to show how the perspective plays an important role in the noncommutative function theory that arises in free analysis and in Baruch Solel’s and my work on tensor operator algebras. The operator algebras involved may be represented as algebras of bonafide operatorvalued, analytic functions with remarkable properties. That is, the operator algebras are repreented as noncommutative function algebras.
These, in turn, prove to be a fertile environment in which to apply Arveson’s theory of subalgebras of C^{*}algebras.
 David Pitts (of University of NebraskaLincoln)
 Title: Unique PseudoExpectations, Dynamics, and Minimal Norms
(slides)
 Yiu Tung Poon (of Iowa State University)
 Title: Compression, Matrix Range and Completely Positive Map
(slides)
 April 30, 2016
 Sergei Bezuglyi (of University of Iowa)
 Title: Harmonic functions on wratteli diagrams
(slides)
 Jon Brown (of University of Dayton)
 Title: A ``Weyl type'' groupoid for Leavitt path algebas
 Abstract: Given a Cartan subalgebra A of C^{*}algebra B, Renault (2008) constructed a topologically principal groupoid whose reduced groupoid C^{*}algebra is isomorphic to B and where the isomorphism restricts to an isomorphism of the canonical Cartan subalgebra of C_r^{*}(G) to A. However there are many interesting examples abelian subalgebras of a given C^{*}algebra that are not Cartan; for example given a directed graph E that doesn't satisfy condition L, the subalgebra D(E) generated by the range and source projections of paths in a graph algebra C^{*}(E). Recently, Brownlowe, Carlsen and Whittaker constructed a ``Weyl type'' groupoid for this inclusion: importantly their construction relies only on the algebra and not the graph itself. They showed that this Weyl groupoid is isomorphic to the graph groupoid and thus an isomorphism from C^{*}(E) to C^{*}(F) that is ``diagonal preserving'' in the sense that it restricts to an isomorphism of D(E) to D(F) gives an isomorphism of the graph groupoids. In this talk, I present joint work with Clark and an Huef, which follows Brownlowe et al to construct a Weyl groupoid for Leavitt path algebra. We use this construction to prove that for ``diagonal preserving'' *ring isomorphisms of Leavitt path algebras, the resulting C^{*}algebras must also be isomorphic: proving a special cases of the AbramsTomforde isomorphism conjecture.
 Rolando de Santiago (of University of Iowa)
 Title: Product rigidity for the von Neumann algebras of hyperbolic groups
(slides)
 Rachel Norton (of University of Iowa)
 Title: Comparing Two Generalized NevanlinnaPick Theorems
(slides)
 Eric Weber (of Iowa State University)
 Title: Fourier and Harmonic Analysis of Measures
(slides)
 March 28, 2015 (the first meeting at Creighton University in Omaha)
 Danny Cryster (of Kansas State University)
 Title: The abelian core and the trace space of a graph algebra
(slides)
 Abstract: The abelian core of a graph algebra is a MASA which has nice stateextension properties. The spectrum of the abelian core encodes information about the pure states of the graph algebra. We describe the trace space of a graph algebra as the set of measures on this spectrum which satisfy a certain natural covariance condition. Joint work with Gabriel Nagy.
 Jennifer Good (of University of Iowa)
 Title: Toward a complete Pick Property in a W^{*}Setting
(slides)
 Sarah Reznikoff (of Kansas State University)
 Title: Graph, kGraph, and Groupoid C*algebras (cancelled)
(slides)
 Jason Ekstrand (of Iowa State University)
 Title: Positivity in Function Algebras
(slides)
 Travis Russell (of University of NebraskaLincoln)
 Title: Order Bounded Maps and Operator Spaces
(slides)
 October 19, 2014 .
 John Haussermann (of University of Central Florida)
 Title: On Spectra of a Cantor Measure
(slides)
 Adam Fuller (of University of NebraskaLincoln)
 Title: Von Neumann Algebras and Extensions of Inverse Semigroups
(slides)
 Abstract: In the 1970s, Feldman and Moore classified separably acting von Neumann algebras contain ing Cartan MASAs using measured equivalence relations and 2cocycles on such equivalence relations. In this paper, we give a new classification in terms of extensions of inverse semigroups. By avoiding most measure theory, our approach is simpler, and allows for the classification of all Cartan pairs, even those which do not act separably. Our approach is more algebraic in character and less pointbased than that of FeldmanMoore.
 Chris Schafhauser (of University of NebraskaLincoln)
 Title: AFEmbeddings of Graph Algebra
(slides)
 Abstract: In the late 1990's, Blackadar and Kirchberg asked if every separable, nuclear, stably finite C*algebra can be embedded into an AFalgebra. We will discuss this conjecture for the class of graph C*algebras and CuntzPimsner algebras. In particular, if either that E is a discrete graph or that E is a compact topological graph with no sinks and C*(E) is finite, then C*(E) is AFembeddable. Also if E is a totally disconnected topological quiver and C*(E) is stable finite, then C*(E) is AFEmbeddable.
 Baruch Solel (of Technion, Israel)
 Title: Matricial Families and Weighted Shifts
(slides)
 April 19, 2014 .
 Robert Pluta (of University of Iowa)
 Title: Corners of C*algebras
(slides)
 Philip Gipson (of University of Nebraska)
 Title: The Invariant Basis Number Property for C*Algebras
(slides)
 Jon Brown (of Kansas State University)
 Title: Purely infinite simple C*algebras associated to etale groupoids
(slides)
 Abstract: Let G be a Hausdorff, etale groupoid that is minimal and topologically principal.
In this talk, we reduce the problem of checking if C^{*}_{r}(G) is purely infinite
to checking that elements of C_{0}(G^{(0)}) are infinite
in C^{*}_{r}(G).
In particular, we show that C^{*}_{r}(G) is purely infinite simple
if and only if all the nonzero
positive elements of C_{0}(G^{(0)}) are infinite in C^{*}_{r}(G).
If G is also ample, then we show that C^{*}_{r}(G) is purely infinite simple
if and only if every nonzero projection in C_{0}(G^{(0)})
is infinite in C^{*}_{r}(G).
We then show how this result applies to kgraph C*algebras.
This work is joint with Lisa Clark and Adam Sierakowski.
 Dima KaliuzhnyiVerbovetskyi (of Drexel University)
 Title: Free Noncommutative Functions: An Introduction
(slides)
 Abstract: This talk is intended to be a brief introduction to noncommutative function theory
that derives from the free algebra in the same sense that ordinary analytic functions may be derived from the
polynomial algebra. The fundamental difference is that in the theory of polynomials and ordinary
analytic functions, a polynomial determines a single function of one or more variables, depending
on where one starts. However, in the theory I will be discussing, an element in the free algebra
determines a whole sequence of functions, each one of which is matrixvalued. The problem is
to understand how all these sequences fit together and to base a general theory upon them. This
idea originated in the work of Joe Taylor in the early 1970s. It lay fallow for some years, and
only recently has exploded into a fullfledged theory. This talk is intended to give an introduction
to the theory, which is exposed in detail in my soontobe published book with Victor Vinnikov,
Foundations of Noncommutative Function Theory.
 November 9, 2013.
 Sergli Berzuglyi (of University of Iowa)
 Title: Full groups of transformations in measurable, Borel, and Cantor dynamics
 Michael Hartglass (of University of Iowa)
 Title: Planar Algebras and thier graded structure
 Matthew Kennedy (of Carleton University)
 Title: The Choquet boundary of an Operator System
(slides)
 Abstract: In this talk, I will discuss the recent solution (with Ken Davidson) of Arveson's conjecture on the existence of the noncommutative Choquet boundary of an operator system. This is an intrinsic invariant of an operator system that plays a fundamental role in Arveson's approach to the study of noncommutative dilation theory and nonselfadjoint operator algebras. I will also mention some recent work (with Orr Shalit) connecting these ideas to the essential normality of a commuting tuple.
 Gabriel Picioroaga (of University of South Dakota)
 Title: Cuntz algebras, generalized Walsh bases, and applications
(slides)
 Spring 2013.
There was a very nice AMS special session at the AMS regional meeting at Iowa State.
 November 3, 2012.
 Sa'ud AlSa'Di (of Iowa State University)
 Title: Sampling and interpolation in Hilbert spaces of entire functions
 Jeff Blanchard (of Grinnel College)
 Title: Greedy Algorithms in Compressed Sensing: Theory and Software
 Adam Fuller (of University of Nebraska at Lincoln)
 Title: Nonselfadjoint 2graph algebras
 Palle Jorgensen (of the University of Iowa)
 Title: An instance of spectrum vs geometry: The universal tiling conjecture
 April 14, 2012.
 Allan Donsig (of University of Nebraska at Lincoln)
 Title:
Tight Representations and Inverse Semigroups
(slides)
 David Milan (of University of Texas at Tyler)
 Title:
Crossed Product Results for Inverse Semigroup C*algebras
(slides)
 Andrew Greene (of University of Iowa)
 Title:
Extensions of Hilbert Modules over Tensor Algebras
(slides)
 Woo Young Lee (of Seoul National University)
 Title:
Hyponormality of block Toeplitz operators
 Anchalee Khemphet (of Iowa State University)
 Title:
The Jacobson radical of semicrossed products of the disk algebra
(slides)
 Dominic Kramer (of Iowa State University)
 Title:
Basis Identification through Convex Optimization
 October 1416, 2011.
The fall 2011 meeting was held jointly with the AMS regional meeting in Lincoln.
There were several relevant special sessions:
 November 67, 2010.
The fall 2010 meeting was held jointly with Groupoidfest 2010.
It is scheduled for November 6  7, 2010
at Creighton University in Omaha.
For more information, see the
Groupoidfest 2010 website.
 April 17, 2010.
 Nikolai Vasilevski, (of CINVESTAV (Mexico) and Princeton Univ.)
 Title:
Commutative algebras of Toeplitz operators in action
(slides)
 Lawrence Fialkow, (of SUNY at New Paltz)
 Title:
The role of "positivity" in moment and polynomial optimization problems
(slides)

Paulette Willis, (of Univ. of Iowa)
 Title:
Labeled graph C*algebras with group actions
(slides)

FlorianHoria Vasilescu, (of Univ. de Lille and Univ. of Iowa)
 Title:
Truncated Moment Problems via Riesz Functionals
 November 15, 2009.
 Yiu Poon (of Iowa State University)
 Title: Completely Positive Maps in Quantum Information
(slides)
 David Pitts (of the University of NebraskaLincoln)
 Title: Embeddings and the Dradical of an Inclusion
 Lance Nielsen (of Creighton University)
 Title: Feynman's Operational Calculi : Background
and a Survey of Current Research
(slides)
 April 25, 2009.
 Dennis Courtney (of the University of Iowa)
 Title: Exact constants in dilation theory
(slides)
 Martha Gregg (of Augustana University)
 Title: C*Extreme Points of the Generalized State Space of a Commutative
C*Algebra
(slides)
 Sam Schmidt (of the University of Iowa)
 Title: Endomorphisms, The Toeplitz Algebra, and Complication Operators
(slides)
 April 12, 2008.
 Victor Kaftal (of the University of Cinncinati)
 Title: Diagonals of positive operators
 Valentin Matache (of University of Nebraska at Omaha)
 Title: Some problems in functional operator theory exhibiting a
nice interplay between operator theory and function theory
 Yiu Poon (of Iowa State University)
 Title: Rank k numerical range in quantum information
 Erin Pearse (of the University of Iowa)
 Title: Operator theory of electrical resistance networks
 April 1, 2006.
 Ken Davidson (of the University of Waterloo; visiting Nebraska)
 Title: Isomorphisms of topological conjugacy algebras
 Doug Farenick (of the University of Regina)
 Title: Injective envelopes and local multipliers of C*algebras
 Palle Jorgensen (of the University of Iowa)
 Title: From signals to operator theory to wavelets
 October, 2005
 There was no meeting. Instead, people went to one or both of the
American Mathematical Society
Regional Meeting
or Groupoidfest 2005.
 The AMS regional meeting is in Lincoln, NE on October 2123.
 Groupoidfest 2005 is at Iowa State University on November 56.
 April 23, 2005
 Stefan Bildea (of the University of Iowa)
 Title: Freeness and Cost in the context of triangle amalgams of C*algebras
and measurable equivalence relations
 John Orr (of the University of NebraskaLincoln)
 Title: Classifying stable ideals of nest algebras
 Jasang Yoon (of Iowa State University)
 Title: Subnormality of Bergmanlike weighted shifts
 October 30, 2004
 Steve Kaliszewski (of Arizona State University; visiting The University of Iowa).
 Title: Symmetric Imprimitivity Theorems and `Hash Products'
 Alex Kumjian (of The University of Nevada, Reno)
 Title: Actions of Z^{k} associated to higher rank graphs
 V.S. Sunder (of The Institute of Mathematical Sciences, Chennai, India; visiting The University of Iowa).
 Title: A complete family of numerical invariants for a subfactor.
 Eric Weber (of Iowa State University)
 Title: Group Representations and Wavelet Transforms
 April, 2004
 There is no meeting. Instead, go to the
CBMS conference by Iain Raeburn on
Graph Algebras: Operator Algebras We Can See,
from May 31 to June 4, 2004.
 October 11, 2003
 Lawrence Fialkow (of SUNY at New Paltz)
 Title: Solution to truncated and full moment problems
on planar curves of degree 2
 Paul Muhly (of the University of Iowa)
 Title: Function Theory from Tensor Algebras
 Jean Renault (of Université d'Orléans)
 Title: AP Groupoids
 Ryan Zerr (of the University of North Dakota)
 Title: Characterizing and studying AF C*algebras
 April 12, 2003
 Valentin Matache (of University of Nebraska at Omaha)
 Title: Complex Dynamics and Composition Operators
 Lance Nielsen (of Creighton University)
 Title: A Survey of Feynman's Operational Calculus
 Konrad Schmuedgen (of Universitat Leipzig)
 Title: A polar decomposition for holomorphic functions on a strip
 David Pitts (of the University of NebraskaLincoln)
 Title:Automorphisms and Coordinates for Triangular Algebras
 October 19, 2002
 Baruch Solel (of the Technion, Israel)
 Title: The Curvature and Index for Completely Postive Maps
 Jack Spielberg (of Arizona State Univ.)
 Title: Generalized graphs and semiprojective C*algebras
 Alan Hopenwasser (of Univ. of AlabamaTuscaloosa)
 Title: Subalgebras of Cuntz C*algebras
 Mark Tomforde (of University of Iowa)
 Title: GaugeInvariant Uniqueness for Relative CuntzPimsner Algebras
 April 13, 2002
 Andu Nica (of Waterloo)
 Title: Rcyclic families of matrices in free probability
 David Larson (of Texas A & M)
 Title: Frames, Wavelets and Operator Theory
 Eric Weber (of Texas A & M)
 Title: The Geometry of Affine Frames
 Palle Jorgensen (of University of Iowa)
 Title: Wavelets, operators, and algorithms: two kinds!
 October 13, 2001
 Elias Katsoulis (of East Carolina University)
 Title: Representations for Operator Algebras and
Applications to their Facial Structure
 Serban Stratila (of University of Iowa)
 Title: The Commutation Theorem for Tensor Products of
Operator Algebras over Subalgebras
 Devin Greene (of University of Nebraska at Lincoln)
 Title: Free Resolutions in Multivariable Operator Theory
 Dorin Dutkay (of University of Iowa)
 Title: The Wavelet Galerkin Operator
 April 13, 2001
A
special meeting was held in Lincoln, in connection with V.F.R. Jones's
Rowlee Lecture.
 October 14, 2000
 Maria Tjani (of University of Arkansas)
 Title: Compact composition operators on some subspaces of
the Bloch space
 Wolfgang Kliemann (of Iowa State University)
 Title: Spectra of Flows on Vector Bundles
 Srdjan Petrovic (of Western Michigan University)
 Title: On the \lambdacommutativity of Volterra operators
 David Kribs (of University of Iowa)
 Title: Dilation theory and Cuntz representations
 April 22, 2000
 Lawrence Fialkow (of SUNY at New Paltz)
 Title: The quartic moment problem
 David Pitts (of University of NebraskaLincoln)
 Title: Invariants for Triangular Limit Algebras
under Algebraic Isomorphisms
 Jacqui Ramagge (of University of Newcastle, Australia)
 Title: Haagerup bounds: Results and conjectures
 David Pask (of University of Newcastle, Australia)
 Title: The ideal structure of graph C*algebras
 October 30, 1999
 Stephen Power (of Lancaster University, U.K.)
 Title: Classifying limits of Finite Dimensional Algebras
 Sergei Silvestrov (of University of Iowa)
 Title: Bounded and unbounded operator representations of
generalised Lie algebras and their deformations
 Valentin Matache (of University of Nebraska at Omaha)
 Title: Numerical Ranges, Composition Operators,
and Computer Assisted Analysis
 N. Diep (of University of Iowa)
 Title: A Survey of Noncommutative Chern Characters
 April 17, 1999
 V. S. Sunder (of Institute of Mathematical Sciences,
Madras, India)
 Title: From Ergodic Theory to Subfactors
 Terje Sund (of University of Oslo)
 Title: Groups with Trivial Cortex
 Victor Kaftal (of University of Cincinnati)
 Title: Regular sequences, operator ideals, commutators and traces
 Liming Ge (of University of New Hampshire)
 Title: Matrix Models, Free Entropy and Factors of type II_1
October 17, 1998
 Gary Weiss (of University of Cinncinnati)
Madras, India)
 Title: The commutator structure of operator ideals and unitarily
invariant trace extensions beyond the trace class
 Michael Lamourexu (of University of Calgary)
 Title: Ideals in Continuous Crossed products
 Paul Muhly (of University of Iowa)
 Title: On the Morita equivalence of C*correspondences
 Roger Smith (of Texas A&M University)
 Title: Cohomology of von Neumann algebras with Cartan subalgebras
October 11, 1997
 May Nilsen (of the University of NebraskaLincoln)
 Title: Hopf C*algebras
 Randall Crist (of Creighton University)
 Title: Derivations on TAF Algebras
 Nik Weaver (of Washington University in St. Louis)
 Title: Metrics from the Point of View of Functional Analysis)
 Radu Gologan (of the University of Iowa and the Institute of Mathematics of
Romanian Academy of Sciences)
 Title: Pointwise Ergodic Theorems
April 26, 1997
 Teresa Bermudez (of the University of Iowa and University de Laguana, Spain)
 Title: Some Results in Local Spectral Theory
 Dale Buske (of Iowa State University and St. Cloud State University)
 Title: Hilbert Modules over a class of Semicrossed Products
 Bryan Cain (of Iowa State University)
 Title: Operator Equations, Inertia, and Stability
 EuiChai Jeong (of the University of Iowa)
 Title: Decomposition of the Cuntz Algebra Representation