#KindAT — Intentional Abstraction Facet for Kinds (K0…K3)

C.3.5 · Cluster C.I - Core CALs / LOGs / CHRs · Stable · Part C - Kernel Extension Specifications

#About this pattern

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#How to use this pattern

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One-line summary. KindAT is an informative editorial facet on one local U.Kind. Its anchors—K0 Instance, K1 Behavioral Pattern, K2 Formal Kind/Class, and K3 Up-to-Iso—help plan declaration rigor, assurance coverage, bridge expectations, catalog search, and refactoring. KindAT is not a Characteristic: it has no algebra or threshold and never appears in guards or composition. It changes neither the kind, a KindSignature, a classification judgment, an extension representation, nor F–G–R.

Status. Informative for anchors, heuristics, examples, and guidance; normative only for the usage rules that prohibit guard/composition use and constrain placement.

Placement. Part C (Kinds), identifier C.3.5. Audience: engineering managers, architects, editors, and assurance leads.

Depends on.

• C.3/C.3.1: the context-local U.Kind, obtaining U.SubkindOf relations, and kind continuity.
• C.3.2: the separate KindSignature declaration episteme, exact four-input classification judgment, and optional pinned-edition extension representation.
• C.3.3: the obtaining KindBridge relation and its separate bridge-assertion episteme carrying CL^k, loss, evidence, and admitted use.
• C.3.4: the RoleMask declaration episteme and exact masked judgment.
• A.2.6, C.2.2, and C.2.3: Claim/Work scope, F–G–R, and U.Formality on the episteme that owns it.
• MM-CHR: the Facet-versus-Characteristic distinction.

Non-goals. KindAT supplies no numerical scale, gating rule, composition operator, public-kind admission, classification result, or assurance score.

Teams need a quick answer to a planning question: is this local kind intended as a curated instance-like cohort, a behavioral pattern, a formal invariant-bearing kind, or a kind considered up to structural equivalence? The answer can guide where declaration rigor and assurance effort are likely to pay off without pretending that abstraction itself widens scope, raises formality, settles classification, or increases reliability.

#Keywords

• KindAT
• K0-K3
• editorial facet
• declaration planning
• assurance planning.

#Relations

#Content

#Purpose

Teams need a quick answer to a planning question: is this local kind intended as a curated instance-like cohort, a behavioral pattern, a formal invariant-bearing kind, or a kind considered up to structural equivalence? The answer can guide where declaration rigor and assurance effort are likely to pay off without pretending that abstraction itself widens scope, raises formality, settles classification, or increases reliability.

KindAT gives that planning vocabulary while keeping the governing objects separate:

• the local kind and its order remain under C.3/C.3.1;
• the KindSignature remains a declaration episteme whose own U.Formality may change;
• J(candidate, kind, signatureEdition, slice) remains true, false, or unknown;
• any KindExtension remains a pinned-edition representation of true candidates; and
• bridge and mask objects retain the ontology assigned by C.3.3 and C.3.4.

#Orthogonality and rationale

• G says where a claim or Work use applies.
• a local kind says what the declaration and claim are about.
• a KindSignature declaration episteme states the reusable criterion and has its own F when current.
• R says how well a receiving claim or use is supported.
• KindAT is only a catalog and planning tag on the local kind.

Calling KindAT a Characteristic would invite a second scope axis, an abstraction score, or a hidden classification gate. Keeping it as a facet lets editors search and plan without adding another truth-bearing or assurance-bearing object.

#Anchors K0…K3 (informative)

#K0 — Instance-level

Intent. The local kind is used for named exemplars or a tightly curated cohort.

Cues. The reusable criterion, when one is needed, relies mainly on direct identity features or an enumerated bounded candidate domain.

Non-example. A stable invariant-bearing distinction belongs nearer K2 even if few candidates are currently known.

Planning. Prefer exact slice-bound judgments and assurance over the current candidate domain. Cross-context reuse is likely to need explicit instance correspondence and may have low CL^k.

#K1 — Behavioral pattern

Intent. The local kind is recognized through repeatable behavior or role-like performance rather than a mature formal invariant set.

Cues. A KindSignature may use controlled prose, behavioral obligations, or executable acceptance predicates.

Non-example. A kind with stable explicit predicates and order relations belongs nearer K2.

Planning. Invest in making the signature criterion evaluable and in testing behavioral diversity. Bridges are usually pattern correspondences whose assertions must state loss.

#K2 — Formal kind/class

Intent. The local kind has explicit invariants, relations, and a reviewed position in a local kind order.

Cues. A reusable KindSignature declaration episteme pins predicate-like criteria, dependencies, and reference scheme; judgments are replayable under exact editions.

Non-example. An informal cohort or role cue does not become K2 merely because it is stored in a schema.

Planning. Consider raising the declaration episteme's F where the receiving use warrants it; plan R across relevant subkinds and boundary cases. KindBridge assertions may support medium or high CL^k only from demonstrated signature/order preservation.

#K3 — Up-to-Iso

Intent. The kind's governed criterion is invariant under a declared isomorphism or equivalence notion.

Cues. Structural equivalence, rather than individual identity, is load-bearing in the signature and receiving use.

Non-example. A class whose candidate identity matters beyond the declared structure is not K3.

Planning. Require explicit equivalence witnesses and receiver acceptance. High CL^k is justified only when the obtaining bridge and its assertion demonstrate preservation of the relevant equivalence structure.

#Manager heuristics (informative)

These are planning cues, not default F values, R values, classification results, or CL^k assessments.

#Misuse and antidotes (informative)

• “Higher KindAT means wider G.” Wrong: only the scope governor changes G.
• “Gate on KindAT.” Wrong: use the exact classification, scope, evidence, and policy predicates required by the receiving guard.
• “Depth in U.SubkindOf determines KindAT.” Wrong: the facet concerns intentional stance, not graph depth.
• “KindAT belongs on the claim or signature.” Wrong: the tag is on the local kind; a catalog may represent that assignment.
• “A reused RoleMask has been promoted automatically.” Wrong: if the distinction is conceptual and stable, separately identify a local kind and establish any obtaining U.SubkindOf relation under C.3.1.
• “KindAT rates quality.” Wrong: formality belongs to the relevant episteme and assurance belongs to the receiving support path.

#Usage rules (normative)

AT-01 (Facet, not Characteristic). KindAT SHALL be treated as a Facet per MM-CHR. It has no algebra or threshold and MUST NOT appear in guard predicates or composition math.

AT-02 (Placement). If recorded, KindAT SHALL characterize one exact local U.Kind under an effective reference scheme. A catalog row may represent that assignment. KindAT MUST NOT be attached to a claim, capability, KindSignature episteme, candidate, judgment, or extension as a substitute for its own governor.

AT-03 (No F–G–R effect). Editors SHALL NOT imply that a higher KindAT widens G, raises the signature episteme's F, increases R, or changes a classification value. Any such sentence MUST name the actual declaration, scope, evidence, or receiving-use change.

AT-04 (Bridge neutrality). Neither an obtaining KindBridge relation nor its bridge-assertion episteme computes or alters KindAT. The assertion may record an informative anchor comparison, but CL^k remains a separate assessment of the admitted bridge use from demonstrated signature/order preservation and loss.

AT-05 (Catalog representation). When a context uses KindAT, its catalog SHOULD identify the local kind and effective reference scheme and reference, rather than collapse, the current KindSignature edition, obtaining subkind relations, RoleMask declaration editions, KindBridge occurrences/assertions, and optional extension representations. Absence of a tag means “not set”, not K0.

#Authoring and review guidance (informative)

#Fast rubric

• Concrete exemplars or a bounded cohort suggest K0.
• Behavioral obligations with few stable global invariants suggest K1.
• Explicit invariant-bearing criteria and a reviewed local order suggest K2.
• An explicit, load-bearing equivalence notion suggests K3.

#Review questions

1. Is the tagged object the exact local kind rather than its signature, card, candidate, claim, or extension?
2. Does the anchor describe the kind's intentional stance rather than the current number of candidates?
3. Are proposed F and R changes stated as planning decisions over their actual owners rather than effects of KindAT?
4. Does a stable mask distinction require a separately identified kind and independently obtaining subkind relation?
5. Does cross-context use recover the exact KindBridge occurrence and separate bridge assertion instead of inferring congruence from the tag?

#Integration notes (informative)

• C.3.1/C.3.2. KindAT may guide work on the signature declaration and assurance plan; it changes neither kind continuity nor the four-input judgment.
• C.3.3. KindAT may suggest what preservation evidence to seek. The bridge assertion, not the tag, carries CL^k, loss, evidence, and admitted use.
• C.3.4. Repeated mask use is a review cue only. A new local kind and any U.SubkindOf relation are established independently.
• A.2.6. Scope remains G on the claim or Work use. KindAT never supplies coverage.
• C.2.3. The relevant declaration or claim episteme owns F. KindAT can motivate investment but cannot assign the value.

#Worked mini-examples (informative)

• K0. Account_US_GAAP_2025_Q1_Cohort: use exact candidate judgments in the pinned quarter slice; do not infer a broad kind from one query result.
• K1. CacheableRequest: make retry/idempotence behavior evaluable in a named signature edition and test diverse failure modes.
• K2. Account: use explicit posting and balance invariants, test relevant subkinds, and evaluate each candidate with the exact signature edition and slice.
• K3. UndirectedGraph up to node relabeling: state the equivalence notion and require bridge/evidence witnesses that preserve it.

#Conformance checklist (normative)

#C.3.5:End

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Last Updated: 2026-08-04 — upstream FPF commit 8b727cba (github.com/ailev/FPF)