research: ZigZag/zzstructure deep dive (information space as orthogonal dimensions); UC-47/48/49

Evaluated modelling a wiki information space as a zzstructure: a page is
a cell at the intersection of many co-equal dimensions (namespace tree,
created-from genealogy, version, shard, equivalence, links).
Recommendation: adopt zzstructure as a navigation/visualization/indexing
LENS (a derived dimensional projection over the union), not as the
storage substrate — Git and sovereign shards stay canonical, and the
many-to-many link graph does not fit the one-neighbour-per-dimension rank
rule. Clone <-> transclusion convergence with the Xanadu dive. Added
UC-47/48/49; enriched UC-05/22/26/29; dimensional projection layer +
genealogy-edges-in-journal logged as architecture for SHARD-WP-0002.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

spec/UseCaseCatalog.md

@@ -5,8 +5,8 @@ Status: **draft** · Date: 2026-06-08 · Updated: 2026-06-14
 Promoted from `research/260608-c2-wiki-origins/`,
 `research/260608-yawex-prior-art/`, `research/260608-federation-concepts/`,
 `research/260608-wikiengines-overview/`, `research/260613-xwiki-deep-dive/`,
-`research/260613-twiki-deep-dive/`, `research/260613-foswiki-deep-dive/`, and
-`research/260614-xanadu-deep-dive/`.
+`research/260613-twiki-deep-dive/`, `research/260613-foswiki-deep-dive/`,
+`research/260614-xanadu-deep-dive/`, and `research/260614-zigzag-deep-dive/`.
 See InfoTechPrimers on coulomb.social for use-case catalog conventions.
 
 ## Conventions
@@ -72,7 +72,11 @@ all attached shards as a federated graph.
 **Source:** intent, c2, yawex  
 **Notes:** Present on both c2 (community nerve center) and yawex core pages.
 BackLinks over the union link-graph is the strongest core candidate; per-shard
-vs union scope remains open (see UC-19–UC-21).  
+vs union scope remains open (see UC-19–UC-21). ZigZag deep dive reframes these views
+under one vocabulary: each is a **dimension + raster** (RecentChanges along `d.recent`,
+AllPages along `d.alphabetical`, SiteMap as an H-view over the namespace dimensions),
+navigable via UC-47 (`research/260614-zigzag-deep-dive/findings.md` §5). Note: the
+many-to-many link/backlink graph stays a **separate graph index**, not a zz-rank.  
 **Priority:** Later
 
 ### UC-06 — Authenticated team wiki (L2+)
@@ -107,7 +111,9 @@ shard for independent editing, with provenance preserved.
 **Notes:** Fedwiki fork primitive. shard-wiki may realize as import, overlay
 seed, or writable copy per policy — distinct from UC-04 (overlay without copy)
 and UC-03 (projection only). Fork vs overlay vs import decided in
-`SHARD-WP-0002`.  
+`SHARD-WP-0002`. Should record a **created-from genealogy edge** in the coordination
+journal so the lineage is navigable as a dimension (UC-49,
+`research/260614-zigzag-deep-dive/findings.md` §9).  
 **Priority:** Later
 
 ### UC-27 — View multiple versions of equivalent page
@@ -144,7 +150,8 @@ per-shard history. Frictionless reuse principle (~15s not ~15min). Xanadu
 **transcopyright**: a reference carries provenance *and reuse terms* with it, so
 attribution/permission travel with the span — but reuse policy stays configurable, not
 baked into the substrate (`research/260614-xanadu-deep-dive/findings.md` §6); links the
-authz-in-core L0→L4 ladder decision.  
+authz-in-core L0→L4 ladder decision. Remix should also record a **genealogy edge**
+(UC-49) so reuse lineage is navigable, not just attributed.  
 **Priority:** Later
 
 ### UC-30 — Time-bounded collaboration space
@@ -397,6 +404,45 @@ normalized-text hash, none). Open: core vs. adapter-index; cost at wiki scale wi
 enfilades (findings §11 Q3).  
 **Priority:** Later
 
+### UC-47 — Navigate the information space along a chosen relationship dimension
+
+**Actor:** Reader  
+**Goal:** Traverse pages along a *selected* relationship axis — namespace, created-from
+genealogy, version history, owning shard, equivalence, or recent-change order — rather
+than a single fixed hierarchy.  
+**Source:** zigzag, intent  
+**Notes:** ZigZag/zzstructure treats each relationship as a first-class **dimension**;
+a page is a cell at the intersection of many independent ranks
+(`research/260614-zigzag-deep-dive/findings.md` §2, §5). Reframes the existing derived
+views (UC-05, UC-17–UC-20) as *dimensions + rasters* under one vocabulary. Embodies
+union-without-erasure: every relationship co-equal, none privileged. Open: public
+navigation API vs. internal model (findings §10 Q1).  
+**Priority:** Later
+
+### UC-48 — Pivot two relationships into a cross-tab view (H-view)
+
+**Actor:** Reader  
+**Goal:** Cross-tabulate the union by two dimensions at once — e.g. namespace × shard,
+or page × versions-across-shards — and pivot to re-cross by a different pair.  
+**Source:** zigzag  
+**Notes:** ZigZag **H-view** shows two dimensions through a cursor, one horizontal one
+vertical, with only existing cells present (`research/260614-zigzag-deep-dive/findings.md`
+§3). A differentiated exploration primitive for federation/provenance. Open: reference-UI
+investment vs. research-only (findings §10 Q4).  
+**Priority:** Later
+
+### UC-49 — Navigate created-from / fork genealogy as a first-class dimension
+
+**Actor:** Reader or maintainer  
+**Goal:** Follow a page's derivation lineage — what it was forked/remixed/imported
+from, and what was derived from it — as a navigable rank.  
+**Source:** zigzag, federation, intent  
+**Notes:** Genealogy is a *functional* relation (one origin) that fits a zzstructure
+dimension natively (`research/260614-zigzag-deep-dive/findings.md` §4, §5). Requires a
+genealogy edge recorded at fork/remix/import time (UC-26, UC-29) in the coordination
+journal. Makes provenance a traversal, not a buried footer (complements UC-24).  
+**Priority:** Later
+
 ---
 
 ## B. Knowledge work and collaboration
@@ -550,7 +596,11 @@ adapter-provided indexing TBD.
 normalized paths within a topic hierarchy.  
 **Source:** yawex  
 **Notes:** yawex topics-as-directories; page-resolution state space is
-inspiration only for federation design (not inherited as API).  
+inspiration only for federation design (not inherited as API). ZigZag deep dive: treat
+the namespace hierarchy as **one dimension among many** (encoded left-child/right-sibling
+as two zz-dimensions), not the privileged structure — consistent with mechanism over
+policy; navigate it as one axis via UC-47 (`research/260614-zigzag-deep-dive/findings.md`
+§4, §7.1).  
 **Priority:** Later
 
 ### UC-23 — Soft topic creation via red link
@@ -625,6 +675,9 @@ CamelCase and `[[free links]]`. Markdown-first link semantics TBD.
 | UC-44 | | | ✓† | | ✓ |
 | UC-45 | | | ✓† | | ✓ |
 | UC-46 | | | ✓† | | ✓ |
+| UC-47 | | | ‡ | | ✓ |
+| UC-48 | | | ‡ | | |
+| UC-49 | | | ‡ | | ✓ |
 | UC-08 | ✓ | | |
 | UC-09 | ✓ | | |
 | UC-10 | ✓ | | |
@@ -743,6 +796,33 @@ single-global-docuverse premise, single-canonical-instance model, and baked-in e
 policy (findings §8.2), as these violate shard sovereignty, parallel-version support
 (UC-27), and mechanism-over-policy.
 
+### zigzag mapping
+
+(‡ UC-47–UC-49 are placed in the **federation** matrix column as the nearest existing
+source; their true lineage is the **ZigZag deep dive**,
+`research/260614-zigzag-deep-dive/findings.md`.)
+
+| ZigZag / zzstructure mechanism (findings §) | Catalog UC |
+|---------------------------------------------|------------|
+| Each relationship is a first-class **dimension**; a page is a cell at many ranks (§2, §5) | UC-47 |
+| **H-view** — pivot two dimensions into a cross-tab (§3) | UC-48 |
+| **Genealogy** as a functional dimension fitting a zz-rank (§4, §5) | UC-49 |
+| Hierarchy is **one dimension among many** (left-child/right-sibling) (§4, §7.1) | UC-22 (enriched) |
+| Derived views = **dimensions + rasters** under one vocabulary (§5) | UC-05 (enriched; anchors UC-17–UC-20) |
+| Fork/remix records a navigable genealogy edge (§9) | UC-26, UC-29 (enriched) |
+| **Clone** = "same content in many places" — converges with transclusion (§5) | links UC-32, UC-44/45 |
+
+Note: ZigZag is **a data model + visualization paradigm, not a candidate shard
+backend.** Recommendation recorded in the dive: adopt zzstructure as a **navigation /
+visualization / indexing lens** — a *derived dimensional projection* over the union,
+like BackLinks today — and **reject it as the storage substrate**
+(`research/260614-zigzag-deep-dive/findings.md` §6, §7.2). Git and sovereign shards
+remain canonical (INTENT Stability Note). The many-to-many hyperlink graph does **not**
+fit zzstructure's one-neighbour-per-dimension rule and stays a separate graph index.
+Architecture logged for `SHARD-WP-0002`: a dimensional projection layer; genealogy
+edges in the coordination journal; clone↔transclusion as a possible shared primitive
+(findings §9). Pairs with the Xanadu dive (clone ↔ transclusion convergence).
+
 ---
 
 ## Open questions
@@ -756,4 +836,8 @@ policy (findings §8.2), as these violate shard sovereignty, parallel-version su
    `ProductRequirementsDocument.md` as explicit product identity?
 5. Which federation UCs (UC-26–UC-33) are **MVP** vs deferred until
    `SHARD-WP-0002` architecture decisions land?
-6. Does UC-32 (transclusion) belong in core orchestrator or adapter/UI layer?
+6. Does UC-32 (transclusion) belong in core orchestrator or adapter/UI layer?
+7. Is the **dimensional/zzstructure model** (UC-47/48) a public navigation API and UI
+   paradigm, or only an internal organizing concept for the derived views?
+8. How is the **many-to-many link graph** reconciled with the rank-based dimensional
+   model — clones, a parallel graph index, or both? (ZigZag dive §10.)