nLab division

Contents

Contents

Idea

The inverse operation to multiplication.

Definition

 In an Euclidean domain

See Euclidean domain

In a field

Given a Heyting field FF, let us define the type of all terms in FF apart from 0:

F #0{aF|a#0}F_{#0} \coloneqq \{a \in F \vert a # 0\}

The division function is a binary function ()():F×F #0F\frac{(-)}{(-)}:F \times F_{#0} \to F defined as

xyx1y\frac{x}{y} \coloneqq x \cdot \frac{1}{y}

where

1y\frac{1}{y}

is the reciprocal function.

Division of finite sets

Given finite set AA and pointed set BB with an element p:Bp:B, one can construct finite sets A÷BA \div B and A%BA\ \%\ B with a bijection

A((B×(A÷B))+(A%B))A \simeq ((B \times (A \div B)) + (A\ \%\ B))

and a bijection

(BA%B)(B \hookrightarrow A\ \%\ B) \simeq \emptyset

A finite pointed set BB is a divisor of AA if there is a bijection (A%B)(A\ \%\ B) \simeq \emptyset:

A|B(A%B)A \vert B \coloneqq (A\ \%\ B) \simeq \emptyset

Last revised on February 27, 2024 at 06:30:33. See the history of this page for a list of all contributions to it.