SPHERE Thread Conventions

This note defines how SPHERE models cross-domain concepts that do not fit a strict tree.

Core Rules

1. SPHERE is graph-native. Branches and twigs are navigation views.
2. A leaf may belong to one or many twigs.
3. Twig membership is descriptive, not exclusive ownership.
4. Cross-domain relations are explicit threads, not only tags.
5. Tags are for filtering and search, not semantic relation logic.

Leaf Membership Model

Each leaf can declare:

• twig_membership: one or many twig aliases
• primary_lens: optional preferred entry lens for navigation
• threads: explicit relation ids connecting this leaf to one twig per thread
• flow_mode: gauge for place-fixed state series, or ant for moving-entity traces
• temporal_mmu: minimum meaningful update cadence (static, episodic, stream)

When a concept is intrinsically cross-domain, primary_lens can be omitted.

The ant metaphor is encoded as flow_mode: ant and should be used for trajectories, routes, and moving actors.

Thread Contract

Each thread must define:

• id: stable edge id
• source: id of the originating entity (leaf, realization, or anchor)
• predicate: the directional verb — chosen from the standard predicate vocabulary below
• target: id of the receiving entity (leaf, twig, realization, or anchor)
• leaf: source leaf id (for cross-twig threads; same as source when source is a leaf)
• twig: target twig alias (for cross-twig threads; same as target when target is a twig)
• relation_type: coarse semantic category of the connection (for agent filtering)
• question: what this edge helps answer
• rationale: short explanation

Standard Predicate Vocabulary

Predicate	Meaning	Typical source → target
determines	Source is a causal or constraining factor for target	Leaf → Leaf
is_property_of	Source describes an attribute of target	Leaf → Leaf
influences_classification_of	Source contributes evidence to a classification decision in target	Leaf → Leaf
realizes_intent_of	Source dataset is the concrete evidence for the question posed by target	Realization → Leaf
anchored_by	Source is spatially or legally pinned to target unit	Realization → Anchor
framed_by	Source uses target as its coordinate reference system	Realization → CRS Leaf
conflicts_with	Source and target disagree on the same question (World of Discourse flag)	Realization → Realization
mandated_by	Target authority defines or legally requires source	CRS Leaf → Governance Anchor
is_primary_evidence_for	Source is the canonical input type for target twig	Leaf → Twig
cross_twig_relevance	Source is relevant to target twig without belonging there primarily	Leaf → Twig

Thread granularity rule:

• One thread connects one entity to one entity.
• If a leaf is relevant to five twigs, create five threads.
• Do not use multi-target thread arrays.

Thread-Only Model

Threads are the canonical cross-domain relation model. Do not add alias fields for older terminology in new files.

Initial Reference Example

See Bathing Water Quality for a concrete multi-twig leaf using one-thread-per-twig links.