subduction

1. (geology) The process of one tectonic plate moving beneath another and sinking into the mantle at a convergent plate boundary.Examples: "Therefore, both a mantle plume and also the subductions of the oceanic plates may have mutually contributed to create the magmatic zone."; "Evidence for a subduction polarity flip is clear in the Irish Caledonides, where the S-dipping slab beneath the Lough Nafooey arc (Dewey & Ryan 1990; Clift & Ryan 1994) became a N-dipping subduction zone after the Grampian Orogeny."; "Earthquakes on the subduction interface itself are low-angle thrusts in the depth range 15–45 km, generally reaching a maximum depth of 20 km in the west and 45 km in the centre of the arc, near Crete."countableuncountable

2. (mathematics, mathematical analysis) A surjection between diffeological spaces such that the target is identified as the pushforward of the source.Examples: "Accordingly, a diffeological principal S¹-bundle over a diffeological space X is a subduction π : P → X and a smooth map τ satisfying the same conditions; see [30] for a thorough discussion."; "Subductions (art. 1.46) express a global behavior of some surjections. As we localized the notion of induction and then obtained the notion of local induction (art. 2.15), the notion of subduction can be localized, or refined, as well, and leads to the concept of local subduction. Exercise 61, p. 60, illustrates the case where a subduction is not everywhere a local subduction."countableuncountable