Fresh productive owners for unary pushes #
A fresh singleton block introduced by a push is owned by the child's depth-one event. This file isolates the two facts needed to allocate that owner: it can coincide with a parent event only at parent depth zero (and only when the child has no depth-zero event), and it is absent from a fully accounted cursor whenever either that parent depth-zero frame is absent or the child itself has a depth-zero event.
A child's depth-one event is inside the equal-count productive window of its push parent.
Exact collision characterization for the depth-one push owner. It aliases a parent event precisely when that event is depth zero and the child has no event at depth zero.
The shadow-bank depth-one ticket has the same collision behavior as its primary mate.
The child depth-one shadow ticket remains inside the equal-count parent shadow window.
If no parent depth-zero owner is held by a frame, the child's depth-one owner is fresh from all frames. Outside-window frames cannot collide because unary windows have equal extent.
If the child already has a depth-zero event, injectivity separates its depth-one owner from every possible local depth-zero frame.
Once frame freshness is known, the full cursor decomposition proves that the canonical depth-one push owner is absent from every persistent index.
Full-cursor push freshness when the parent depth-zero owner is not held by a frame.
Full-cursor push freshness when child depths zero and one are both productive events.
Schedule-ledger specialization of depth-one push freshness with an explicit frame premise.
Schedule-ledger push freshness when no parent depth-zero owner is framed.
Schedule-ledger push freshness when child depths zero and one both carry events.
If the canonical depth-one child owner is already persistent, the unique collision is an open parent depth-zero frame. In particular, the child cannot itself have a depth-zero event.
If child depths zero and one are both events, the depth-one shadow ticket is absent from an entirely accounted parent semantic cursor. It is neither a parent shadow event nor an outside-window ticket.