Further Conjugation Results

  • Heinz H. Bauschke
  • Patrick L. Combettes
Part of the CMS Books in Mathematics book series (CMSBM)


In this chapter, we exhibit several deeper results on conjugation. We first discuss Moreau’s decomposition principle, whereby a vector is decomposed in terms of the proximity operator of a lower semicontinuous convex function and that of its conjugate. This powerful nonlinear principle extends the standard linear decomposition with respect to a closed linear subspace and its orthogonal complement. Basic results concerning the proximal average and positively homogeneous functions are also presented. Also discussed are the Moreau–Rockafellar theorem, which characterizes coercivity in terms of an interiority condition, and the Toland–Singer theorem, which provides an appealing formula for the conjugate of a difference.

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© Springer International Publishing AG 2017

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Authors and Affiliations

  • Heinz H. Bauschke
    • 1
  • Patrick L. Combettes
    • 2
  1. 1.Department of MathematicsUniversity of British ColumbiaKelownaCanada
  2. 2.Department of MathematicsNorth Carolina State UniversityRaleighUSA

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