συνυπάρχουσαν καὶ παρυφεστηκυῖαν τῷ πρωτοτύπῳ ὑποστήσαντι.  Expressions of this kind, used even by Basil, may help to explain the earlier Nicene sense of ὑπόστασις.  The Son has, as it were, a parallel hypostasis to that of the Father, Who eternally furnishes this hypostasis.  cf. p. 195, n.