@UNPUBLISHED{publication1, title = "On a conjecture about the comparability of parallel systems with respect to convex transform order", author = "{ARAB, Idir} and {HADJIKYRIAKOU, Milto} and {OLIVEIRA, Paulo Eduardo}", year = "2019-01-08", abstract = " In this paper we prove that two heterogeneous parallel systems with independent exponentially distributed components are comparable via the star transform order while the comparison via the convex transform fails. The latter conclusion provides a partial answer to a problem that remained open for a decade. ", url = "http://www.mat.uc.pt/preprints/eng\_2019.html", note = "" }