An endpoint of a line segment is a point that belongs to the boundary of . Note that every line segment has two distinct endpoints. For example, if is a vector space and with , then the endpoints of the line segment are and .
Note that the endpoints of the open line segment are also and .
Endpoints can be defined in a similar manner for other geometric objects. These include rays, arcs, and intervals.
![[parent]](http://images.planetmath.org:8080/images/uparrow.png)
![$ \displaystyle L = \{ a+tb : t\in[0,1]\}$](http://images.planetmath.org:8080/cache/objects/8165/l2h/img6.png "$ \displaystyle L = \{ a+tb : t\in[0,1]\}$"){kind=small}
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