A function is convex if its epigraph is convex. This geometrical structure has very strong implications in terms of continuity and differentiability. Separation theorems lead to optimality conditions and duality for convex problems. A function is quasiconvex if its lower level sets are convex. Here again, the geo metrical structure of the level sets implies some continuity and differentiability properties for quasiconvex functions. Optimality conditions and duality can be derived for optimization problems involving such functions as well. Over a period of about fifty years, quasiconvex and other generalized convex functions have been considered in a variety of fields including economies, man agement science, engineering, probability and applied sciences in accordance with the need of particular applications. During the last twenty-five years, an increase of research activities in this field has been witnessed. More recently generalized monotonicity of maps has been studied. It relates to generalized convexity off unctions as monotonicity relates to convexity. Generalized monotonicity plays a role in variational inequality problems, complementarity problems and more generally, in equilibrium prob lems."

Simone Young leads the Bayerisches Staatsorchester in this production of Pfitzner's opera, directed for the stage by Christian Stuckl. Performers include Christopher Ventris, Peter Rose, Michael Volle and Falk Struckmann.

A function is convex if its epigraph is convex. This geometrical structure has very strong implications in terms of continuity and differentiability. Separation theorems lead to optimality conditions and duality for convex problems. A function is quasiconvex if its lower level sets are convex. Here again, the geo metrical structure of the level sets implies some continuity and differentiability properties for quasiconvex functions. Optimality conditions and duality can be derived for optimization problems involving such functions as well. Over a period of about fifty years, quasiconvex and other generalized convex functions have been considered in a variety of fields including economies, man agement science, engineering, probability and applied sciences in accordance with the need of particular applications. During the last twenty-five years, an increase of research activities in this field has been witnessed. More recently generalized monotonicity of maps has been studied. It relates to generalized convexity off unctions as monotonicity relates to convexity. Generalized monotonicity plays a role in variational inequality problems, complementarity problems and more generally, in equilibrium prob lems."

Franz Welser-Möst conducts the Orchestra and Chorus of the Zurich Opera House in this performance of Johann Strauss's work filmed in 2001. David Poutney directs with Martin Zysset in the title role and the cast including Michael Volle, Elizabeth Magnuson and Piotr Beczala.

A production of Debussy's opera featuring the orchestra and chorus of the Zurich Opera House, conducted by Franz Welser-Möst. Recorded in 2004, performers include Rodney Gilfry, Isabel Rey, Michael Volle and László Polgár.

Christoph von Dohnanyi conducts the Zurich Opera House Orchestra in this live recording of Richard Strauss's opera from 2006. Performers include American soprano Emily Magee, Elena Mosuc, and Italian tenor Roberto Saccà.