TY - JOUR ID - Micherda2015 LB - Micherda2015 AU - Micherda, Bartosz TI - A new characterization of convex φ-functions with a parameter ST - A new characterization of convex φ-functions with a parameter JO - Opuscula Math. JA - Opuscula Math. JF - Opuscula Mathematica PY - 2015 VL - 35 IS - 2 SP - 191 EP - 197 DO - http://dx.doi.org/10.7494/OpMath.2015.35.2.191 UR - http://dx.doi.org/10.7494/OpMath.2015.35.2.191 AB - We show that, under some additional assumptions, all projection operators onto latticially closed subsets of the Orlicz-Musielak space generated by \(\Phi\) are isotonic if and only if \(\Phi\) is convex with respect to its second variable. A dual result of this type is also proven for antiprojections. This gives the positive answer to the problem presented in Opuscula Mathematica in 2012. KW - Orlicz-Musielak space KW - convex function KW - isotonic operator KW - projection operator KW - antiprojection operator SN - 1232-9274 ER -