Struct F4QuotientShape 

pub struct F4QuotientShape<const COMPONENT_LABEL_BYTES: usize>;

F₄-via-quotient composition shape — the unary quotient construction on the Atlas image inside E₈ per wiki [ADR-059]’s categorical-operation vocabulary.

F₄ is the rank-4 exceptional Lie algebra reached from the Atlas by the 96 / ± mirror-symmetry quotient (48 sign classes). As a categorical operation, F₄ is a quotient of one Atlas structure under mirror symmetry — the shape is therefore unary by structural necessity: SITE_COUNT = COMPONENT_LABEL_BYTES. A single operand κ-label is canonicalized into its mirror-symmetry equivalence class before σ-projection.

The composed κ-label addresses the operand’s equivalence class under the quotient, not the operand directly. Two operands that are mirror-symmetric per the realization’s commitment compose to byte-identical composed κ-labels.

See also

• crate::std_types for the family contract and IRI namespace.
• G2ProductShape / E6FiltrationShape / E7AugmentationShape / E8EmbeddingShape for the other four categorical operations on the Atlas.
• crate::convergence for the convergence-tower vocabulary ADR-059 commits.
• Wiki: 05 Building Block View § Whitebox prism
• Wiki: 09 Architecture Decisions § ADR-059
• Wiki: 09 Architecture Decisions § ADR-061
• AGENTS.md § 11

Constraints

• TC-01 — admission is compile-time.
• TC-04 — bilateral compile-time enforcement.
• ADR-013 — closure under uor-foundation.
• ADR-017 — content-addressed identity via the IRI.
• ADR-058 — κ-derivation produces the composed κ-label.
• ADR-059 — codomain factors through the Atlas image inside E₈.
• ADR-061 — operational composition surface for κ-labels.

Behavior

use prism::pipeline::ConstrainedTypeShape;
use prism::std_types::F4QuotientShape;

// Given a unary F₄ quotient over one sha256 κ-label (71 bytes),
type F = F4QuotientShape<71>;
// When SITE_COUNT is queried,
// Then it equals the operand width — F₄'s quotient is unary.
assert_eq!(<F as ConstrainedTypeShape>::SITE_COUNT, 71);
assert_eq!(
    <F as ConstrainedTypeShape>::IRI,
    "https://uor.foundation/type/ConstrainedType",
);
assert!(<F as ConstrainedTypeShape>::CONSTRAINTS.is_empty());

Trait Implementations

impl<const COMPONENT_LABEL_BYTES: usize> ConstrainedTypeShape for F4QuotientShape<COMPONENT_LABEL_BYTES>

const IRI: &'static str = "https://uor.foundation/type/ConstrainedType"

IRI of the ontology type:ConstrainedType instance this shape represents.

const SITE_COUNT: usize = COMPONENT_LABEL_BYTES

Number of sites (fields) this constrained type carries.

const CONSTRAINTS: &'static [ConstraintRef]

Per-site constraint list. Empty means unconstrained.

const CYCLE_SIZE: u64

ADR-032: cardinality of the shape’s value-set (the cycle structure of the shape under the substrate’s discrete-clock model). Used by the prism_model! macro to lower first_admit (closure-body grammar G16) to the correct descent measure. Conventions:

const SITE_BUDGET: usize = Self::SITE_COUNT

Ontology-level siteBudget: count of data sites only, excluding bookkeeping introduced by composition (coproduct tag sites, etc.). Equals SITE_COUNT for leaf shapes and for shapes whose composition introduces no bookkeeping (products, cartesian products). Strictly less than SITE_COUNT for coproduct shapes and any shape whose SITE_COUNT includes inherited bookkeeping. Introduced by the Product/Coproduct Completion Amendment §4a; defaults to SITE_COUNT so pre-amendment shape impls remain valid without edits.