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## Partial groupoids

Abbreviation: Pargoid

### Definition

A partial groupoid is a structure $\mathbf{A}=\langle A,\cdot\rangle$, where

$\cdot$ is a partial binary operation: $\exists D\subseteq A\times A(\cdot:D\to A)$.

Remark: $x\cdot y\in A\iff \langle x,y\rangle\in D$

##### Morphisms

Let $\mathbf{A}$ and $\mathbf{B}$ be partial groupoids. A morphism from $\mathbf{A}$ to $\mathbf{B}$ is a function $h:A\rightarrow B$ that is a homomorphism: if $x\cdot y\in A$ then $h(x \cdot y)=h(x) \cdot h(y)$

### Examples

Example 1: The empty partial binary operation on any set $A$ gives a partial groupoid.

### Properties

Feel free to add or delete properties from this list. The list below may contain properties that are not relevant to the class that is being described.

Classtype first-order

### Finite members

$\begin{array}{lr} f(1)= &2\\ f(2)= &45\\ f(3)= &\\ f(4)= &\\ f(5)= &\\ \end{array}$ $\begin{array}{lr} f(6)= &\\ f(7)= &\\ f(8)= &\\ f(9)= &\\ f(10)= &\\ \end{array}$

### Subclasses

[[Groupoids]]
[[Partial semigroups]]

### Superclasses

[[Ternary relations]]