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sqsubseteq

Denotes a square subset relation where one set is contained within another, commonly used in mathematical set theory and order theory.

Overview

Represents a fundamental ordering relation in mathematics, particularly useful in formal logic, computer science, and abstract algebra.

  • Essential in lattice theory for describing partial orders
  • Used to express subset relationships with additional semantic meaning
  • Common in formal specifications and mathematical proofs
  • Appears frequently in theoretical computer science when describing type systems or program semantics
  • Often paired with its strict counterpart \sqsubset in formal mathematical writing

Examples

Defining a partial order relation in set theory.

AB    ABA \sqsubseteq B \implies |A| \leq |B|
A \sqsubseteq B \implies |A| \leq |B|

Expressing subset relationships in domain theory.

x\bot \sqsubseteq x \sqsubseteq \top
\bot \sqsubseteq x \sqsubseteq \top

Comparing information content in lattice theory.

xyz    xzx \sqsubseteq y \sqsubseteq z \implies x \sqsubseteq z
x \sqsubseteq y \sqsubseteq z \implies x \sqsubseteq z