Duoprism

Set of uniform p-q duoprisms
Type	Prismatic uniform 4-polytopes
Schläfli symbol	{p}×{q}
Coxeter-Dynkin diagram
Cells	p q-gonal prisms, q p-gonal prisms
Faces	pq squares, p q-gons, q p-gons
Edges	2pq
Vertices	pq
Vertex figure	disphenoid
Symmetry	[p,2,q], order 4pq
Dual	p-q duopyramid
Properties	convex, vertex-uniform
Set of uniform p-p duoprisms
Type	Prismatic uniform 4-polytope
Schläfli symbol	{p}×{p}
Coxeter-Dynkin diagram
Cells	2p p-gonal prisms
Faces	p2 squares, 2p p-gons
Edges	2p2
Vertices	p2
Symmetry	[p,2,p] = [2p,2+,2p], order 8p2
Dual	p-p duopyramid
Properties	convex, vertex-uniform, Facet-transitive

In geometry of 4 dimensions or higher, a double prism^[1] or duoprism is a polytope resulting from the Cartesian product of two polytopes, each of two dimensions or higher. The Cartesian product of an n-polytope and an m-polytope is an (n+m)-polytope, where n and m are dimensions of 2 (polygon) or higher.

The lowest-dimensional duoprisms exist in 4-dimensional space as 4-polytopes being the Cartesian product of two polygons in 2-dimensional Euclidean space. More precisely, it is the set of points:

${\displaystyle P_{1}\times P_{2}=\{(x,y,z,w)|(x,y)\in P_{1},(z,w)\in P_{2}\}}$

where P₁ and P₂ are the sets of the points contained in the respective polygons. Such a duoprism is convex if both bases are convex, and is bounded by prismatic cells.