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6 Polytope
 6.1 Polytope: Category and Representations
 6.2 Polytope: Properties
 6.3 Polytope: Attributes
 6.4 Polytope: Methods

  6.4-1 *

  6.4-2 #
 6.5 Polytope: Constructors
 6.6 Polytope: Examples

6 Polytope

6.1 Polytope: Category and Representations

6.1-1 IsPolytope
‣ IsPolytope( M )( category )

Returns: true or false

The GAP category of a polytope. Every polytope is a convex object.

Remember: Every cone is a convex object.

6.2 Polytope: Properties

6.2-1 IsNotEmpty
‣ IsNotEmpty( poly )( property )

Returns: true or false

Checks if the polytope poly is not empty.

6.2-2 IsLatticePolytope
‣ IsLatticePolytope( poly )( property )

Returns: true or false

Checks if the polytope poly is a lattice polytope, i.e. all its vertices are lattice points.

6.2-3 IsVeryAmple
‣ IsVeryAmple( poly )( property )

Returns: true or false

Checks if the polytope poly is very ample.

6.2-4 IsNormalPolytope
‣ IsNormalPolytope( poly )( property )

Returns: true or false

Checks if the polytope poly is normal.

6.2-5 IsSimplicial
‣ IsSimplicial( poly )( property )

Returns: true or false

Checks if the polytope poly is simplicial.

6.2-6 IsSimplePolytope
‣ IsSimplePolytope( poly )( property )

Returns: true or false

Checks if the polytope poly is simple.

6.3 Polytope: Attributes

6.3-1 Vertices
‣ Vertices( poly )( attribute )

Returns: a list

Returns the vertices of the polytope poly. For reasons, the corresponding tester is HasVerticesOfPolytopes

6.3-2 LatticePoints
‣ LatticePoints( poly )( attribute )

Returns: a list

Returns the lattice points of the polytope poly.

6.3-3 FacetInequalities
‣ FacetInequalities( poly )( attribute )

Returns: a list

Returns the facet inequalities for the polytope poly.

6.3-4 VerticesInFacets
‣ VerticesInFacets( poly )( attribute )

Returns: a list

Returns the incidence matrix of vertices and facets of the polytope poly.

6.3-5 AffineCone
‣ AffineCone( poly )( attribute )

Returns: a cone

Returns the affine cone of the polytope poly.

6.3-6 NormalFan
‣ NormalFan( poly )( attribute )

Returns: a fan

Returns the normal fan of the polytope poly.

6.3-7 RelativeInteriorLatticePoints
‣ RelativeInteriorLatticePoints( poly )( attribute )

Returns: a list

Returns the lattice points in the relative interior of the polytope poly.

6.4 Polytope: Methods

6.4-1 *
‣ *( polytope1, polytope2 )( operation )

Returns: a polytope

Returns the Cartesian product of the polytopes polytope1 and polytope2.

6.4-2 #
‣ #( polytope1, polytope2 )( operation )

Returns: a polytope

Returns the Minkowski sum of the polytopes polytope1 and polytope2.

6.5 Polytope: Constructors

6.5-1 Polytope
‣ Polytope( points )( operation )

Returns: a polytope

Returns a polytope that is the convex hull of the points points.

6.5-2 PolytopeByInequalities
‣ PolytopeByInequalities( ineqs )( operation )

Returns: a polytope

Returns a polytope defined by the inequalities ineqs.

6.6 Polytope: Examples

6.6-1 Polytope example
gap> P := Polytope( [ [ 2, 0 ], [ 0, 2 ], [ -1, -1 ] ] );
<A polytope in |R^2>
gap> IsVeryAmple( P );
true
gap> LatticePoints( P );
[ [ -1, -1 ], [ 0, 0 ], [ 0, 1 ], 
[ 0, 2 ], [ 1, 0 ], [ 1, 1 ], [ 2, 0 ] ]
gap> NFP := NormalFan( P );
<A complete fan in |R^2>
gap> C1 := MaximalCones( NFP )[ 1 ];
<A cone in |R^2>
gap> RayGenerators( C1 );
[ [ -1, -1 ], [ -1, 3 ] ]
gap> IsRegularFan( NFP );
true
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