Symbol Reference: ‹ ... › — Explicit Syntactic Quotation Brackets (Syntax Coding: A.Expression → Class)

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‹ ... › \(\lsaquo \dots \rsaquo\) — Explicit Syntactic Quotation Brackets (Syntax Coding: A.Expression → Class)

Encodes an already formed finite syntactic formula or expression e : A.Expression into its canonical hereditary set code Enc_A(e) ∈ Code_A ⊆ V inside MKTD1 and MKTD2 (does not reify arbitrary unnameable semantic classes into syntax).

Field Mathematical & Kernel Specification (MKTD1 / MKTD2)
Symbol
‹ ... ›
\(\lsaquo \dots \rsaquo\)
Category Quotation & Antiquotation (Reflection Layer)
SML AST Constructor Kernel AST Symbol / Sort Constructor in typetheory.ML (Class_p / Truth_p / EXP / UCol)
Constructor Arguments Typed arguments as specified by the Signature / Sort field above
Metatype / Signature A.Expression → Class (or Fm → Class)
Binder Status See Category & Signature above
Defining Kernel Entries (ML Labels) See Related Symbols & Kernel Entries below.
LaTeX Form \lsaquo \dots \rsaquo
How to Understand It

In the Morse-Kelley + Tarski + Dunaev (MKTD1 / MKTD2) foundational framework, ‹𝛂› denotes explicit syntactic quotation (Corner / Guillemet Quotation). Rather than confusing a formula 𝛂 : Fm (or expression e : A.Expression) with its semantic denotation or its code inside the universe of classes, quotation explicitly maps finite syntax into the valid-code carrier Code_A ⊆ V:

  • Acts on Existing Syntax (Not Arbitrary Semantic Reification): Quotation consumes an already represented finite syntactic expression e : A.Expression and produces its set code Enc_A(e) : Class. By the cardinal/diagonal obstruction in 130_classes_as_types.tex, countable finite syntax cannot name every semantic class (e.g. every function N → {0,1}), nor is semantic valuation injective on syntax (Enc(‹0+0›) ≠ Enc(‹0›) despite equal denotation).
  • Compositional Quasi-Quotation: Inside a quoted expression ‹ ... ›, logical connectives and binders are quoted as AST constructors unless spliced at the syntactic level via angle-bracket antiquotation ⟨ ... ⟩.
  • Role in Reflection & Incompleteness: Used throughout Section AxmSoundnessOfBaseTheory (3.72)–ThmDunaevSecondProjection (3.78), Section 4 (Metalogical Laws), and Section 5 (Löb's Theorem ThmLoeb (5.01) and Gödel's Second Incompleteness Theorem ThmSecondIncompleteness (5.02)) to state provability 𝒯 ⊢ ‹𝛂› cleanly.
Canonical Law / Usage (𝒯 ⊢ ‹𝛂›) ∧ (𝒯 ⊢ ‹𝛃›) ⇒ (𝒯 ⊢ ‹𝛂 ∧ 𝛃›)
Related Symbols & Kernel Entries