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Hyperrectangle

Generalization of a rectangle for higher dimensions

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In geometry, a hyperrectangle (also called a box, hyperbox, k-cell or orthotope), is the generalization of a rectangle (a plane figure) and the rectangular cuboid (a solid figure) to higher dimensions. A necessary and sufficient condition is that it is congruent to the Cartesian product of finite intervals. This means that a k-dimensional rectangular solid has each of its edges equal to one of the closed intervals used in the definition. Every k-cell is compact.

If all of the edges are equal length, it is a hypercube. A hyperrectangle is a special case of a parallelotope.

01Formal definition

For every integer i from 1 to k, let a_{i} and b_{i} be real numbers such that a_{i}<b_{i}. The set of all points x=(x_{1},\dots ,x_{k}) in \mathbb {R} ^{k} whose coordinates satisfy the inequalities a_{i}\leq x_{i}\leq b_{i} is a k-cell.

Projections of -cells onto the plane (from ). Only the edges of the higher-dimensional cells are shown.
Projections of -cells onto the plane (from ). Only the edges of the higher-dimensional cells are shown.

02Intuition

A k-cell of dimension k\leq 3 is especially simple. For example, a 1-cell is simply the interval [a,b] with a<b. A 2-cell is the rectangle formed by the Cartesian product of two closed intervals, and a 3-cell is a rectangular solid.

The sides and edges of a k-cell need not be equal in (Euclidean) length; although the unit cube (which has boundaries of equal Euclidean length) is a 3-cell, the set of all 3-cells with equal-length edges is a strict subset of the set of all 3-cells.

03Types

A four-dimensional orthotope is likely a hypercuboid.

The special case of an n-dimensional orthotope where all edges have equal length is the n-cube or hypercube.

By analogy, the term "hyperrectangle" can refer to Cartesian products of orthogonal intervals of other kinds, such as ranges of keys in database theory or ranges of integers, rather than real numbers.

04Dual polytope

n-fusil
Example: 3-fusil
TypePrism
Faces2n
Vertices2n
Schläfli symbol{}+{}+···+{} = n{}
Coxeter diagram ...
Symmetry group[2n−1], order 2n
Dual polyhedronn-orthotope
Propertiesconvex, isotopal

The dual polytope of an n-orthotope has been variously called a rectangular n-orthoplex, rhombic n-fusil, or n-lozenge. It is constructed by 2n points located in the center of the orthotope rectangular faces.

An n-fusil's Schläfli symbol can be represented by a sum of n orthogonal line segments: { } + { } + ... + { } or n{ }.

A 1-fusil is a line segment. A 2-fusil is a rhombus. Its plane cross selections in all pairs of axes are rhombi.

n Example image
1
Line segment
{ }
2
Rhombus
{ } + { } = 2{ }
3
Rhombic 3-orthoplex inside 3-orthotope
{ } + { } + { } = 3{ }
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Sources and credits

This article is adapted from the Wikipedia article Hyperrectangle, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

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