Maximum likelihood estimation for tensor normal models via castling transforms

Open Access
Authors
Publication date 2022
Journal Forum of Mathematics, Sigma
Article number e50
Volume | Issue number 10
Number of pages 23
Organisations
  • Faculty of Science (FNWI) - Institute of Physics (IoP) - Institute for Theoretical Physics Amsterdam (ITFA)
  • Faculty of Science (FNWI) - Korteweg-de Vries Institute for Mathematics (KdVI)
  • Interfacultary Research - Institute for Logic, Language and Computation (ILLC)
Abstract In this paper, we study sample size thresholds for maximum likelihood estimation for tensor normal models. Given the model parameters and the number of samples, we determine whether, almost surely, (1) the likelihood function is bounded from above, (2) maximum likelihood estimates (MLEs) exist, and (3) MLEs exist uniquely. We obtain a complete answer for both real and complex models. One consequence of our results is that almost sure boundedness of the log-likelihood function guarantees almost sure existence of an MLE. Our techniques are based on invariant theory and castling transforms.
Document type Article
Language English
Published at https://doi.org/10.1017/fms.2022.37
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