Duoprism
A duoprism is a 4-
dimensional figure resulting from the Cartesian product of two
polygons in the 2-dimensional Euclidean space. More precisely, it is the
set of points:
where
P1 and
P2 are the sets of the points contained in the respective polygons.
The duoprism is a
convex 4-dimensional
polytope bounded by prismic cells.
Encyclopedia
A
duoprism is a 4-
dimensional figure resulting from the Cartesian product of two
polygons in the 2-dimensional Euclidean space. More precisely, it is the
set of points:
where
P1 and
P2 are the sets of the points contained in the respective polygons.
The duoprism is a
convex 4-dimensional
polytope bounded by prismic cells.
Geometry
A
uniform duoprism is created by the product of a regular
n-sided
polygon and a regular
m-sided polygon is bounded by n
m-gonal prisms and m
n-gonal prisms. For example, the Cartesian product of a triangle and a hexagon is a duoprism bounded by 6 triangular prisms and 3 hexagonal prisms.
- When m and n are identical, the resulting duoprism is bounded by 2n identical n-gonal prisms. For example, the Cartesian product of two triangles is a duoprism bounded by 6 triangular prisms.
- When m and n are identically 4, the resulting duoprism is bounded by 8 tetragonal prisms , and is identical to the hypercube.
The
m-gonal prisms are attached to each other via their
m-gonal faces, and form a closed loop. Similarly, the
n-gonal prisms are attached to each other via their
n-gonal faces, and form a second loop perpendicular to the first. These two loops are attached to each other via their square faces, and are mutually perpendicular.
As
m and
n approach infinity, the corresponding duoprisms approach the duocylinder. As such, duoprisms are useful as non-quadric approximations of the duocylinder.
Nomenclature
The term
duoprism is coined by George Olshevsky. It is a subset of the prismatic polychora. In Olshevsky's usage, a duoprism made of
n-polygons and
m-polygons is named by prefixing 'duoprism' with the names of the base polygons, for example: the
triangular-pentagonal duoprism is the Cartesian product of a triangle and a pentagon.
An alternative, more concise way of specifying a particular duoprism is by prefixing with numbers denoting the base polygons, for example: 3,5-duoprism for the triangular-pentagonal duoprism.
Other alternative names:
- q-gonal-p-gonal prism
- q-gonal-p-gonal double prism
- q-gonal-p-gonal hyperprism
See also
References
- The Fourth Dimension Simply Explained, Henry P. Manning, Munn & Company, 1910, New York. Available from the University of Virginia library. Also accessible online: —contains a description of duoprisms and duocylinders
External links
- —describes duoprisms as "double prisms" and duocylinders as "double cylinders"
- - glossary of higher-dimensional terms
- The word Duoprism is also the name of an . It has no relation to the mathematical use of the term as described here.