## The Mathematical Symbol "Not a Subset Of (⊄)"

The "Not a Subset Of" Symbol (⊄)

In set theory, an integral part of mathematics, the symbol ⊄ denotes that one set is not a subset of another set.

## Decoding ⊄

Given two sets $$A$$ and $$B$$, $$A$$ is said to be a subset of $$B$$ if every element of $$A$$ is also an element of $$B$$. The ⊄ symbol, however, is used to express the opposite: that $$A$$ is not a subset of $$B$$.

Example 1: Basic Sets

Let's say we have two sets, $$A = \{1, 2\}$$ and $$B = \{1, 2, 3, 4\}$$. Although $$A$$ is a subset of $$B$$, if we had a set $$C = \{1, 5\}$$, we could correctly state: $C ⊄ B$

Example 2: Common Misconception

If we consider the set $$D = \{3, 4, 5\}$$ and $$B = \{1, 2, 3, 4\}$$, it might be tempting to think some elements of $$D$$ are in $$B$$. However, because not all elements of $$D$$ are in $$B$$, we represent it as: $D ⊄ B$

## Applications of ⊄

The ⊄ symbol is valuable in various domains, such as:

• Mathematics: Especially in set theory, to define the relationships between sets.
• Research: In academic papers that involve discussions around set relationships.

In summary, the ⊄ symbol is essential for expressing non-subset relationships in the world of set theory, allowing mathematicians to define and analyze set structures with precision.

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## Codes for the ⊄ Symbol

 The Symbol ⊄ Alt Code Alt 8836 HTML Code ⊄ HTML Entity ⊄ CSS Code \2284 Hex Code ⊄ Unicode U+2284

## How To Insert the ⊄ Symbol

(Method 1) Copy and paste the symbol.

The easiest way to get the ⊄ symbol is to copy and paste it into your document.

Bear in mind that this is a UTF-8 encoded character. It must be encoded as UTF-8 at all stages (copying, replacing, editing, pasting), otherwise it will render as random characters or the dreaded �.

(Method 2) Use the "Alt Code."

If you have a keyboard with a numeric pad, you can use this method. Simply hold down the Alt key and type 8836. When you lift the Alt key, the symbol appears. ("Num Lock" must be on.)

(Method 3) Use the HTML Decimal Code (for webpages).

HTML TextOutput
<b>My symbol: &#8836;</b>My symbol: ⊄

(Method 4) Use the HTML Entity Code (for webpages).

HTML TextOutput
<b>My symbol: &nsub;</b>My symbol: ⊄

(Method 5) Use the CSS Code (for webpages).

CSS and HTML TextOutput
<style>
span:after {
content: "\2284";}
</style>
<span>My symbol:</span>
My symbol: ⊄

(Method 6) Use the HTML Hex Code (for webpages and HTML canvas).

HTML TextOutput
<b>My symbol: &#x2284;</b>My symbol: ⊄
On the assumption that you already have your canvas and the context set up, use the Hex code in the format 0x2284 to place the ⊄ symbol on your canvas. For example:
JavaScript Text
const x = "0x"+"E9"
ctx.fillText(String.fromCodePoint(x), 5, 5);
Output

(Method 7) Use the Unicode (for various, e.g. Microsoft Office, JavaScript, Perl).

The Unicode for ⊄ is U+2284. The important part is the hexadecimal number after the U+, which is used in various formats. For example, in Microsoft Office applications (e.g. Word, PowerPoint), do the following:
TypeOutput
2284
[Hold down Alt]
[Press x]

(The 2284 turns into ⊄. Note that you can omit any leading zeros.)
In JavaScript, the syntax is \uXXXX. So, our example would be \u2284. (Note that the format is 4 hexadecimal characters.)
JavaScript TextOutput
let str = "\u2284"
document.write("My symbol: " + str)
My symbol: ⊄