DotContext
The causal history of a replica: every Dot it has ever witnessed, live or already removed. It is the memory that outlives a delete — that is what lets a merge tell "I saw that dot and dropped it on purpose" from "I just haven't seen it yet".
Stored compactly: the contiguous prefix per replica is a version vector (vv: replica → highest contiguous seq), and any non-contiguous dots wait in a cloud until the gaps before them fill, at which point they compact into the vector. The cloud is required because kuilt fabrics reorder and duplicate frames, so dots can arrive out of order.
It is itself a Quilted: piece is the join (union of both histories). Equality is canonical — compaction pushes the cloud as far into the vector as possible and drops already-covered dots — so two contexts with the same causal history are structurally equal, which the conformance laws rely on.
Serialized by DotContextSerializer, which emits both vv and cloud in a canonical sorted order so that two replicas at the same logical state produce identical bytes regardless of delivery order (issue #713).
Functions
This history with dot witnessed (idempotent; compacts the cloud).
The causal Dots this state has delivered — (author, author-seq) per op.
The per-author high-water of dots this state delivered and has since compacted away without retaining their identities.
The join: the union of two causal histories.