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	Dr. Tim Netzer Research fellow Universität Leipzig Mathematisches Institut Group: Algebra Room: 1-16 Johannisgasse 26 Phone: +49-(0)341-97 32186 E-mail:

Teaching

Grundwissen Algebra/Zahlentheorie, Summer Term 2012.

Diskrete Strukturen für Informatiker, Winter Term 2011/12.

Konvexität 2, Winter Term 2011/12.

Konvexität, Summer Term 2011.

Linear Algebra for Physicists, Winter Term 2010/11.

Preprints

• "Real Closed Separation Theorems and Applications to Group Algebras"
  with Andreas Thom.
• "Determinantal Representations and the Hermite Matrix"
  with Daniel Plaumann and Andreas Thom.

Publications

14. "Polynomials with and without Determinantal Representations"
    with Andreas Thom,
    to appear in Linear Algebra and its Applications.
    
    
13. "Positivstellensätze for Real Function Algebras"
    with Murray Marshall,
    Mathematische Zeitschrift 270 (3-4), 889-901 (2012).
    doi:10.1007/s00209-010-0831-1
    
    
12. "Positive Polynomials and Projections of Spectrahedra"
    with João Gouveia,
    SIAM Journal on Optimization 21 (3), 960-976 (2011).
    doi: 10.1137/100801913
    
    
11. "On the Real Multidimensional Rational K-Moment Problem"
    with Jaka Cimpric and Murray Marshall,
    Transactions of the American Mathematical Society 363 (11), 5773-5788 (2011)
    doi:10.1090/S0002-9947-2011-05225-6
    
    
10. "Closures of Quadratic Modules"
    with Jaka Cimpric and Murray Marshall,
    Israel Journal of Mathematics 183 (1), 445-474 (2011).
    doi:10.1007/s11856-011-0056-y
    
    
9. "Tracial Algebras and an Embedding Theorem"
   with Andreas Thom,
   Journal of Functional Analysis 259, 2939-2960 (2010).
   doi:10.1016/j.jfa.2010.08.010
   
   
8. "Representation and Approximation of Positivity Preservers"
   Journal of Geometric Analysis 20 (3), 751-770 (2010).
   doi:10.1007/s12220-010-9126-3
   
   
7. "On Semidefinite Representations of Non-closed Sets"
   Linear Algebra and its Applications 432, 3072-3078 (2010).
   doi:10.1016/j.laa.2010.02.005
   
   
6. "Exposed Faces of Semidefinitely Representable Sets"
   with Daniel Plaumann and Markus Schweighofer,
   Siam Journal on Optimization 20 (4), 1944-1955 (2010).
   doi:10.1137/090750196
   
   
5. "Positive Polynomials and Sequential Closures of Quadratic Modules"
   Transactions of the American Mathematical Society 362, 2619-2639 (2010).
   doi:10.1090/S0002-9947-09-05001-6
   
   
4. "Stability of Quadratic Modules"
   manuscripta mathematica 129 (2), 251-271 (2009).
   doi:10.1007/S00229-009-0258-3
   
   
3. "An Elementary Proof of Schmüdgen's Theorem on the Moment Problem of Closed Semi-Algebraic Sets"
   Proceedings of the American Mathematical Society 136, 529-537 (2008).
   doi:10.1090/S0002-9939-07-09087-9
   
   
2. "A Note on the Representation of Positive Polynomials with Structured Sparsity"
   with David Grimm and Markus Schweighofer,
   Archiv der Mathematik 5, 399-403 (2007).
   doi:10.1007/s00013-007-2234-z
   
   
1. "SOS Approximations of Nonnegative Polynomials via Simple High Degree Perturbations"
   with Jean B. Lasserre,
   Mathematische Zeitschrift 256 (1), 99-112 (2007).
   doi:10.1007/s00209-006-0061-8
   
   

More

• "A Note on the Convex Hull of Finitely Many Projections of Spectrahedra"
  with Rainer Sinn, arXiv:0908.3386v1 [math.OC].
  
• "Positive Polynomials, Sums of Squares and the Moment Problem"
  Phd Thesis, University of Konstanz, 2008.
• "High Degree Perturbations of Nonnegative Polynomials"
  Diploma Thesis, University of Konstanz, 2005.

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