Not Double Left Arrow ⇍

Semantic identity and intent

Characters to distinguish

• ⇒ — Implies
• ⇔ — If and Only If
• → — Right Arrow

Use ⇍ in the right format

Meaning and usage

Represents the not double left arrow in mappings, implications, transformations, limits, or paired processes.

For Not Double Left Arrow (⇍), use this arrow only when its direction, head style, or negation is part of the mathematical meaning; define field-specific uses near the first occurrence.

Pronunciation: not double left arrow

Formula examples

How to type Not Double Left Arrow

Windows

Use Character Map or enter U+21CD in a Unicode-aware application.

macOS

Open Character Viewer with Control–Command–Space and search by the symbol name.

Microsoft Word

In an equation, type \nLeftarrow and press Space when Word supports the command.

iPhone and iPad

Copy and paste ⇍, or use a math/LaTeX app. The standard iOS keyboard may not expose every mathematical symbol.

Android

Copy and paste ⇍, or use a math keyboard or LaTeX editor. Keyboard layouts vary by device and app.

Google Docs

For plain text, paste ⇍ or use Insert → Special characters. For structured math, use the equation editor and verify \nLeftarrow.

Excel

Paste ⇍ into a cell or use Insert → Symbol when available. Ordinary cells preserve the character but do not interpret LaTeX commands.

Common mistakes

• Define the logical convention before using ⇍; proof, programming, and Boolean-algebra sources may assign different precedence or direction.
• For plain text, copy ⇍ as U+21CD; for structured equations, use \nLeftarrow in math mode. A look-alike glyph or image can break search, accessibility, or parsing when the intended character is Not Double Left Arrow.

When to use ⇍

• Use ⇍ in plain text when a Unicode character is appropriate and the destination preserves U+21CD.
• Use \nLeftarrow in an equation editor when mathematical spacing or structure matters.
• Define the local meaning when Not Double Left Arrow is used in arrows, logic with a field-specific convention.

Look-alikes and related characters

• ⇒ — Implies
• ⇔ — If and Only If
• → — Right Arrow

Font and compatibility notes

Glyph shape can vary by font. Verify the code point after copying, and prefer LaTeX or MathML for structured equations.

Review and source notes

Quality tier: specialist

Last reviewed: 2026-07-23

Review method: Catalog review of character identity and notation mappings.

Verified against: Unicode Standard, Unicode mathematical notation guidance, and established LaTeX/MathML syntax.

Reference sources

• The Unicode StandardUnicode Consortium — Character identity, encoding, names, and conformance.
• Unicode Character Code ChartsUnicode Consortium — Code points and official character charts.

Frequently asked questions