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PD Dr. Tim Netzer
Research fellow
University of Leipzig
Mathematical Institute
Group: Algebra
Neues Augusteum, Room 515
Augustusplatz 10
04109 Leipzig
Phone: +49-(0)341-97 32186
E-mail:
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Teaching
Reelle algebraische Geometrie 2, Summer Term 2013.Reelle algebraische Geometrie 1, Winter Term 2012/13.
Algebra 1, Winter Term 2012/13.
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
- "How Fast Do Polynomials Grow on Semialgebraic Sets?"
with Pinaki Mondal. - "Smooth Hyperbolicity Cones are Spectrahedral Shadows"
with Raman Sanyal. - "Hyperbolic Polynomials and Generalized Clifford Algebras"
with Andreas Thom.
Publications
- "Can You Compute the Operator Norm?"
with Tobias Fritz and Andreas Thom,
to appear in Proceedings of the American Mathematical Society.
- "Determinantal Representations and the Hermite Matrix"
with Daniel Plaumann und Andreas Thom,
to appear in Michigan Mathematical Journal.
- "Real Closed Separation Theorems and Applications to Group Algebras"
with Andreas Thom,
to appear in Pacific Journal of Mathematics.
- "Polynomials with and without Determinantal Representations"
with Andreas Thom,
Linear Algebra and its Applications 437 (7), 1579-1595 (2012).
doi:10.1016/j.laa.2012.04.043
- "Positivstellensätze for Real Function Algebras"
with Murray Marshall,
Mathematische Zeitschrift 270 (3-4), 889-901 (2012).
doi:10.1007/s00209-010-0831-1
- "Positive Polynomials and Projections of Spectrahedra"
with João Gouveia,
SIAM Journal on Optimization 21 (3), 960-976 (2011).
doi: 10.1137/100801913
- "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
- "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
- "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
- "Representation and Approximation of Positivity Preservers"
Journal of Geometric Analysis 20 (3), 751-770 (2010).
doi:10.1007/s12220-010-9126-3
- "On Semidefinite Representations of Non-closed Sets"
Linear Algebra and its Applications 432, 3072-3078 (2010).
doi:10.1016/j.laa.2010.02.005
- "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
- "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
- "Stability of Quadratic Modules"
manuscripta mathematica 129 (2), 251-271 (2009).
doi:10.1007/S00229-009-0258-3
- "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
- "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
- "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
- "Spectrahedra and Their Shadows"
Habilitation Thesis, University of Leipzig, 2012. - "Positive Polynomials, Sums of Squares and the Moment Problem"
Doctoral Thesis, University of Konstanz, 2008. - "High Degree Perturbations of Nonnegative Polynomials"
Diploma Thesis, University of Konstanz, 2005.