## The Mathematical Symbol "Double Subset (⋐)"

The Double Subset (⋐): An Introduction

The Double Subset, represented as ⋐ is a mathematical notation often used in set theory. This symbol represents a concept wherein one set is not only a subset of another but is also possibly equal to it. In this article, we will explore the primary use of the Double Subset symbol with two illustrative examples.

## Usage in Set Theory

In set theory, the ⋐ notation is used to denote that one set, say A, is a subset of another set, B, or is equal to B. It encapsulates both the notions of strict subset and non-strict subset.

Example 1:

If we have two sets:

A = {1, 2, 3} and B = {1, 2, 3, 4, 5}

We can rightly say that A ⋐ B, since every element of A is also an element of B.

Example 2:

For the sets:

X = {a, b, c} and Y = {a, b, c}

We can state that X ⋐ Y, since X and Y contain the same elements. Here, the notation also implies X = Y.

These examples demonstrate the versatility of the Double Subset notation in representing relationships between sets. It's essential to understand the context in which it's used, as it can convey different subset relationships based on the given sets.

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## Codes for the ⋐ Symbol

The Symbol | ⋐ | |

Alt Code | Alt 8912 | |

HTML Code | ⋐ | |

HTML Entity | ⋐ | |

CSS Code | \22D0 | |

Hex Code | ⋐ | |

Unicode | U+22D0 |

## 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 8912. 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: "\22D0";} </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: ⋐ |

**0x22D0**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+22D0**. 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 |
---|---|

22D0 [Hold down Alt] [Press x] | ⋐ (The 22D0 turns into ⋐. Note that you can omit any leading zeros.) |

JavaScript Text | Output |
---|---|

let str = "\u22D0" document.write("My symbol: " + str) | My symbol: ⋐ |