τ \(\tau\) — Bourbaki / Unspecified Choice Descriptor Binder (τ)
Variable-binding choice descriptor τx. 𝛗(x) selecting a witness of 𝛗(x) when one exists.
| Field | Mathematical & Kernel Specification (MKTD1 / MKTD2) |
|---|---|
| Symbol |
τ
\(\tau\)
|
| Category | Binder (Choice Descriptor Operator) |
| 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 | (Variable × Fm) → Class |
| Binder Status | See Category & Signature above |
| Defining Kernel Entries (ML Labels) | See Related Symbols & Kernel Entries below. |
| LaTeX Form | \tau |
| How to Understand It | Classification: Binder (variable-binding operator). Distinct symbol page from Hilbert's |
| Canonical Law / Usage | (∃(x:Class)𝛗(x)) → 𝛗(τx. 𝛗(x)) |
| Related Symbols & Kernel Entries |