semi-singleton \(\text{semi-singleton}\) — Semi-Singleton Class Predicate (semi-singleton, Entry DefSemiSingleton (3.35))
Unary predicate asserting that class X has at most one element: ∀(u∈X)∀(v∈X)(u=v) (Entry DefSemiSingleton (3.35)).
| Field | Mathematical & Kernel Specification (MKTD1 / MKTD2) |
|---|---|
| Symbol |
semi-singleton
\(\text{semi-singleton}\)
|
| Category | Predicate Symbol (Unary Class Predicate) |
| SML AST Constructor | SemiSingleton_def_entry [Defined Unary Predicate, entries.ML:DefSemiSingleton (3.35)] |
| Constructor Arguments | 1. Class X : Class |
| Metatype / Signature | Class → Bool |
| Binder Status | No — Unary Predicate Symbol |
| Defining Kernel Entries (ML Labels) | See Related Symbols & Kernel Entries below. |
| LaTeX Form | \text{semi-singleton} |
| How to Understand It | SML AST Constructor: Defined unary class predicate in Entry DefSemiSingleton (3.35) ( |
| Canonical Law / Usage | (X is a semi-singleton) ⟷ ∀(u∈X)∀(v∈X)(u=v) |
| Related Symbols & Kernel Entries |