Nicholas Young

Research Professor
Department of Pure Mathematics
Leeds University

Research interests

Mathematical analysis, particularly operators on Hilbert space; complex analysis; H infinity control.

Current research

I am collaborating with Jim Agler (UC San Diego), Zinaida Lykova (Newcastle University) and John E. McCarthy (Washington University) on a) function theory of the symmetrised bidisc and b) the extension of some classical theorems of function theory to functions of two or more variables.

Recent articles

My most recent papers are:

• A case of mu-synthesis as a quadratic semidefinite program, December 2012, joint with Jim Agler and Z. A. Lykova.
  

• Correction to `A Schwarz Lemma for a domain related to mu-synthesis', February 2013, joint with A. Abouhajar and M. C. White.
  

• Extremal holomorphic maps and the symmetrised bidisc, October 2011, joint with Jim Agler and Z. A. Lykova.
  

• Boundary behavior of analytic functions of two variables via generalized models, March 2012, joint with Jim Agler and Ryan Tully-Doyle;
  

• Nevanlinna representations in several variables, March 2012, joint with Jim Agler and Ryan Tully-Doyle;
  

• On the representation of holomorphic functions on polyhedra, November 2011, joint with Jim Agler and John McCarthy;
  

• Some analysable instances of mu-synthesis, March 2011;
  

• The boundary Caratheodory-Fejer problem, November 2010, joint with Jim Agler and Z. A. Lykova;
  

• Operator monotone functions and Löwner functions of several variables, September 2010, joint with J. Agler and J. E. McCarthy;
  

• Pseudo-Taylor expansions and the Caratheodory-Fejer problem, January 2011, joint with Jim Agler and Z. A. Lykova.

Click here for abstracts and bibliographic details of recent publications (1999-present).
Preprints of papers which have not yet appeared are on the eprint archive.

Here is my full publication list as a pdf file.

Some recent lectures

• Realization of symmetric analytic functions of non-commuting variables, Gargnano, Italy, May2013.
  
• Derivatives of analytic functions on the bidisc and generalized models, Newcastle, February 2013.
  
• Generalized models and slope functions for the Schur class of the bidisc, Joint AMS-MAA Meeting, San Diego, January 2013.
  
• Domains associated with mu-synthesis and magic functions, IWOTA, Sydney, July 2012.
  
• Resolvents and Nevanlinna representations in several variables, Leeds University, March 2012, Oxford University, April 2012 and IWOTA, Sydney, July 2012.
  
• Nevanlinna representations for the two-variable Pick class, Seminar at Newcastle University, February 2012.
  
• An application of operators and invariant distances in control engineering, Colloquia at Washington University, St Louis, October 2011 and Czech Academy of Sciences, Prague, November 2011.
  
• Differential structure of analytic functions on the bidisc at boundary points, Conference in honour of Nikolai Nikolskii, Bordeaux, September 2011.
  
• The structured spectrum of an operator, IWOTA, Seville, July 2011.
  
• Some solvable cases of mu-synthesis, Conference in honour of Bill Helton, San Diego, October 2010.
  
• Boundary behaviour of analytic functions on the bidisc, Ecole d'Analyse, Le Touquet August 2010.
  
• Some interactions between operator theory and control engineering, Workshop on Rigidity and Frameworks, Lancaster, July 2010.
  
• Construction of analytic functions on the bidisc with prescribed boundary behaviour, Conference on Functional Analysis, Valencia, June 2010.
  
• Complex geometry via families of operators, Fifth Advanced Course in Operator Theory and Complex Analysis, Seville, June 2008.
  Lecture 1: Interpolation and Lempert's Theorem
  Lecture 2: A proof of Lempert's Theorem
  Lecture 3: Magic functions
  (The slides have to be read backwards, from p. 22 back to p. 1. Sorry.)

  Click here for lectures going back to 1999 (with slides in some cases).

Former students

Professor Fang-bo Yeh, currently President of Tunghai University, Taichung, Taiwan.
Peter Quiggin. He works for a service company for the offshore oil industry. His thesis Generalisations of Pick's Theorem to Reproducing Kernel Hilbert Spaces is available from Lancaster University Library, or alternatively from here .
David Ogle. He works in the nuclear power industry. Here is his thesis Operator and Function Theory of the Symmetrized Polydisc, 1999, in Newcastle University Library, or alternatively here.
Alaa Abouhajar. Her thesis Function theory related to H infinity control, is accessible in Newcastle University Library.

Contact details

My email address is N.J.Young (at sign) leeds.ac.uk
I am also a Senior Research Investigator in the School of Mathematics and Statistics, Newcastle University.

Updated 6th June, 2013