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xLeftarrow

Creates a double-headed extensible left arrow with text above it, commonly used in mathematical expressions to indicate logical implications or mappings.

Overview

Serves as a versatile arrow notation in mathematical and logical contexts, particularly useful when longer text or expressions need to be displayed above the arrow.

  • Frequently used in formal logic to show reverse implications or "follows from" relationships
  • Common in category theory for depicting morphisms or functors
  • Automatically adjusts its length based on the width of the text argument
  • Part of the AMS-LaTeX extension package, offering enhanced mathematical notation capabilities

Examples

Showing logical implication with a condition above the arrow.

A⇐p∧qBA \xLeftarrow{p \wedge q} B 
A \xLeftarrow{p \wedge q} B

Indicating a reverse mapping with specified constraints.

f(x)⇐x>0yf(x) \xLeftarrow{x > 0} y 
f(x) \xLeftarrow{x > 0} y

Denoting backward dependency with a labeled condition.

Output⇐requiresInput\text{Output} \xLeftarrow{\text{requires}} \text{Input} 
\text{Output} \xLeftarrow{\text{requires}} \text{Input}