line segment


Definition Suppose is a vector space over or , and is a subset of . Then is a line segmentMathworldPlanetmath if can be parametrized as

for some in with .

Sometimes one needs to distinguish between open and closed (http://planetmath.org/Closed) line segments. Then one defines a closed line segment as above, and an open line segment as a subset that can be parametrized as

for some in with .

If and are two vectors in and , then we denote by the set connecting and . This is , . One can easily check that is a closed line segment.

Remarks

  • An alternative, equivalentMathworldPlanetmathPlanetmathPlanetmathPlanetmath, definition is as follows: A (closed) line segment is a convex hull of two distinct points.

  • A line segment is connected, non-empty set.

  • If is a topological vector spaceMathworldPlanetmath, then a closed line segment is a closed set in . However, an open line segment is an open set in if and only if is one-dimensional.

  • More generally than above, the concept of a line segment can be defined in an ordered geometry.

Title line segment
Canonical name LineSegment
Date of creation 2013-03-22 14:19:01
Last modified on 2013-03-22 14:19:01
Owner matte (1858)
Last modified by matte (1858)
Numerical id 12
Author matte (1858)
Entry type Definition
Classification msc 03-00
Classification msc 51-00
Related topic Interval
Related topic LinearManifold
Related topic LineInThePlane
Related topic CircularSegment
Defines open line segment
Defines closed line segment
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