Output feedback pole assignment for transfer functions with symmetries

Uwe Helmke, Joachim Rosenthal, Xiaochang Alex Wang

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


This paper studies the problem of pole assignment for symmetric and Hamiltonian transfer functions. A necessary and sufficient condition for pole assignment by complex symmetric output feedback transformations is given. Moreover, in the case where the McMillan degree coincides with the number of parameters appearing in the symmetric feedback transformations, we derive an explicit combinatorial formula for the number of pole assigning symmetric feedback gains. The proof uses intersection theory in projective space as well as a formula for the degree of the complex Lagrangian Grassmann manifold.

Original languageEnglish
Pages (from-to)1898-1914
Number of pages17
JournalSIAM Journal on Control and Optimization
Issue number5
StatePublished - 2006


  • Degree of a projective variety
  • Inverse eigenvalue problems
  • Lagrangian Grass-mannian
  • Output feedback
  • Pole placement
  • Symmetric or Hamiltonian realizations


Dive into the research topics of 'Output feedback pole assignment for transfer functions with symmetries'. Together they form a unique fingerprint.

Cite this