The Mathematical Symbol "Square Image Of (⊏)"
The "Square Image Of" (⊏)
The ⊏ symbol, commonly known as "Square Image Of", is a mathematical notation used to denote a specific type of relationship between sets. Specifically, it's used to indicate that one set is an image of another under a function when dealing with certain mathematical contexts, especially within set theory and related areas.
Understanding the Symbol
The ⊏ symbol represents the notion that one set, say A, is an image of another set, B, under a specific function f. This means that every element of A has an image in B when mapped by the function f. The "square" nature of the symbol often emphasizes a specific kind of function or relation being considered.
Usage
The exact usage of ⊏ can depend on the mathematical context. In general, it's used to describe relationships between sets under certain functions or transformations. Its main utility is in abstract mathematical discussions where clarity and specificity of notation are paramount.
Example
If we have a function \( f: A \to B \) and using the ⊏ notation, we might say:
\( A ⊏ B \) under \( f \)
This would indicate that set A is an image of set B under the function \( f \).
Typing ⊏
In digital documents or web content, using the ⊏ entity will render the "Square Image Of" symbol. If working with specialized mathematical software or notation systems, other methods might be employed to display or input this symbol.
Related Symbols
Other related symbols include ⊏ (Square Subset Of) and ⊑ (Square Subset of or Equal To). Each of these symbols provides specific information about the relationship between sets in a given mathematical context.
Conclusion
The ⊏ symbol is a testament to the richness of mathematical notation, offering precision and clarity in describing relationships between sets. Its utility, especially in higher mathematics, helps scholars convey complex ideas effectively and succinctly.

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Codes for the ⊏ Symbol
The Symbol | ⊏ | |
Alt Code | Alt 8847 | |
HTML Code | ⊏ | |
HTML Entity | ⊏ | |
CSS Code | \228F | |
Hex Code | ⊏ | |
Unicode | U+228F |
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 8847. When you lift the Alt key, the symbol appears. ("Num Lock" must be on.)(Method 3) Use the HTML Decimal Code (for webpages).
HTML Text | Output |
---|---|
<b>My symbol: ⊏</b> | My symbol: ⊏ |
(Method 4) Use the HTML Entity Code (for webpages).
HTML Text | Output |
---|---|
<b>My symbol: ⊏</b> | My symbol: ⊏ |
(Method 5) Use the CSS Code (for webpages).
CSS and HTML Text | Output |
---|---|
<style> span:after { content: "\228F";} </style> <span>My symbol:</span> | My symbol: ⊏ |
(Method 6) Use the HTML Hex Code (for webpages and HTML canvas).
HTML Text | Output |
---|---|
<b>My symbol: ⊏</b> | My symbol: ⊏ |
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+228F. 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:Type | Output |
---|---|
228F [Hold down Alt] [Press x] | ⊏ (The 228F turns into ⊏. Note that you can omit any leading zeros.) |
JavaScript Text | Output |
---|---|
let str = "\u228F" document.write("My symbol: " + str) | My symbol: ⊏ |