Full Idea
Supervenience is not an ontological relationship, being just modally robust property co-variance.
Clarification
'modally robust' means it persists through most possibilities
Gist of Idea
Supervenience is simply modally robust property co-variance
Source
Robin F. Hendry (Chemistry [2008], 'Ontol')
Book Reference
'Routledge Companion to Philosophy of Science', ed/tr. Psillos,S/Curd,M [Routledge 2010], p.528
A Reaction
I take supervenience to be nothing more than an interesting phenomenon that requires explanation. I suppose Humean Supervenience is a priori metaphysics, since you could hardly explain it.