## The Mathematical Symbol "Square Image of or Equal To (⊑)"

The "Square Image of or Equal To" Symbol (⊑)

The ⊑ symbol, known as "Square Image of or Equal To," represents the mathematical relationship where one set is a subset of another set or is equal to it. It is often used in set theory to discuss the relationships between two sets.

## Understanding the Symbol

Visually, the ⊑ symbol looks like a square subset symbol with an additional horizontal line below, similar to the standard "less than or equal to" sign. The presence of the horizontal line implies the "or equal to" part of the relationship.

## Usage

When used in mathematical contexts, ⊑ communicates that the set on the left side of the symbol is either a subset of or identical to the set on the right side.

For instance, if you have two sets A and B, and A is a subset of or equal to B, this relationship can be denoted as:

$$A \sqsube B$$

## Example

Suppose we have a universal set $$U$$ and a subset $$A$$.

If $$A$$ contains some of the elements of $$U$$ or all the elements of $$U$$, then the relationship can be represented as:

$$A \sqsube U$$

## Typing ⊑

To represent the "Square Image of or Equal To" symbol on platforms or documents that recognize HTML entities, you can use the ⊑ entity. However, the appearance might vary based on the font and platform you're on. In other contexts, software, or platforms, you may need to use a specific keyboard shortcut or another method to represent the symbol.

## Related Symbols

Several symbols in mathematics relate to or resemble ⊑, including:

• ⊏ (Square Subset)
• ⊐ (Square Superset)
• &sqsupsete; (Square Superset of or Equal To)

## Conclusion

The ⊑ symbol is crucial in set theory and helps mathematicians concisely describe relationships between sets. Understanding this and related symbols is vital for anyone diving deep into the world of set theory and related disciplines.

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## Codes for the ⊑ Symbol

 The Symbol ⊑ Alt Code Alt 8849 HTML Code ⊑ HTML Entity ⊑ CSS Code \2291 Hex Code ⊑ Unicode U+2291

## 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 8849. 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: &#8849;</b>My symbol: ⊑

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

HTML TextOutput
<b>My symbol: &sqsube;</b>My symbol: ⊑

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

CSS and HTML TextOutput
<style>
span:after {
content: "\2291";}
</style>
<span>My symbol:</span>
My symbol: ⊑

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

HTML TextOutput
<b>My symbol: &#x2291;</b>My symbol: ⊑
On the assumption that you already have your canvas and the context set up, use the Hex code in the format 0x2291 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+2291. 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
2291
[Hold down Alt]
[Press x]

(The 2291 turns into ⊑. Note that you can omit any leading zeros.)
In JavaScript, the syntax is \uXXXX. So, our example would be \u2291. (Note that the format is 4 hexadecimal characters.)
JavaScript TextOutput
let str = "\u2291"
document.write("My symbol: " + str)
My symbol: ⊑