HTML Entity for Complement (∁)
What You'll Learn
How to display the Complement (∁) symbol in HTML using numeric references, the named entity, and CSS escapes. This character is U+2201 (COMPLEMENT) in the Mathematical Operators block (U+2200–U+22FF). It denotes the complement of a set in set theory and appears in logic and mathematical documentation.
Use the named entity ∁, hex ∁, decimal ∁, or CSS \2201. ∁ is the most readable option when writing HTML by hand. Do not confuse ∁ with Commercial Minus Sign U+2052 (⁒) or punctuation Colon U+003A (:).
⚡ Quick Reference — Complement
U+2201Mathematical Operators (U+2200–U+22FF)
∁Hexadecimal reference
∁Decimal reference
∁Standard HTML entity
Name Value
──────────── ──────────
Unicode U+2201
Hex code ∁
HTML code ∁
Named entity ∁
CSS code \2201Complete HTML Example
This example demonstrates the Complement (∁) using hexadecimal code, decimal HTML code, the named entity ∁, and a CSS content escape:
<!DOCTYPE html>
<html>
<head>
<style>
#point:after{
content: "\2201";
}
</style>
</head>
<body>
<p>Complement using Hexa Decimal: ∁</p>
<p>Complement using HTML Code: ∁</p>
<p>Complement using HTML Entity: ∁</p>
<p id="point">Complement using CSS Entity: </p>
</body>
</html>🌐 Browser Support
U+2201 is supported in modern browsers; use a math-capable font for best glyph quality:
👀 Live Preview
See the Complement symbol in mathematical contexts:
🧠 How It Works
Hexadecimal Code
∁ references code point U+2201 using hex digits 2201.
Decimal HTML Code
∁ is the decimal equivalent (8705) for the same character.
Named HTML Entity
∁ is the standard named entity for U+2201—easy to remember for set complement notation.
CSS Entity
\2201 is the CSS escape for U+2201, used in the content property of ::before or ::after.
Same visual result
All four methods produce the Complement glyph: ∁. Unicode U+2201 sits in Mathematical Operators (U+2200–U+22FF).
Use Cases
The Complement symbol (∁) commonly appears in:
Denote the complement of a set (e.g. ∁A for the complement of set A).
Online courses, textbooks, and lecture notes on discrete mathematics.
Formal logic, Boolean algebra, and computer science documentation.
API references, white papers, and specification documents with math notation.
CMS or tools that output math symbols without MathML.
Unicode tables and Mathematical Operators glossaries.
Provide surrounding text or aria-label so assistive tech conveys set-complement meaning.
💡 Best Practices
Do
- Prefer
∁for readable hand-written HTML - Use math fonts (Cambria Math, STIX Two Math) for clear operator glyphs
- Keep entity style consistent across a document
- Use
\2201only inside CSScontent - Consider MathML or LaTeX for complex equations; entities work for inline symbols
Don’t
- Confuse U+2201 (∁) with Commercial Minus U+2052 (⁒)
- Use a regular hyphen or minus sign instead of ∁ in formal set notation
- Assume every system font renders Mathematical Operators clearly
- Put CSS escape
\2201in HTML text nodes - Mix entity styles randomly in one file
Key Takeaways
Named entity is easiest to remember
∁Numeric references also render ∁
∁ ∁For CSS stylesheets, use the escape in the content property
\2201U+2201 COMPLEMENT (Mathematical Operators)
Four methods, one glyph — widely supported in modern browsers
❓ Frequently Asked Questions
∁ (named entity), ∁ (hex), ∁ (decimal), or \2201 in CSS content. All four methods render ∁.U+2201 (COMPLEMENT). Mathematical Operators (U+2200–U+22FF). Hex 2201, decimal 8705.∁ is the most readable option when writing HTML by hand.∁, ∁, or ∁) go directly in markup. The CSS escape \2201 is used in stylesheets, typically in the content property of pseudo-elements.∁ is the named entity for U+2201. It is well supported and maps to the set-complement operator ∁.Explore More HTML Entities!
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