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# directProduct(Fan,Fan) -- computes the direct product of two fans

- Function: directProduct
- Usage:
    `F = directProduct(F1,F2)`
- Inputs:
  - F1, an instance of the type Fan
  - F2, an instance of the type Fan
- Outputs:
  - F, an instance of the type Fan

## Description

The directProduct of two fans is the fan given by C = C1 x C2 for all cones C1 in F1 and C2 in F2 in the direct product of the ambient spaces.

    i1 : F1 = normalFan hypercube 1

    o1 = {ambient dimension => 1         }
          number of generating cones => 2
          number of rays => 2
          top dimension of the cones => 1

    o1 : Fan

    i2 : F2 = normalFan hypercube 2

    o2 = {ambient dimension => 2         }
          number of generating cones => 4
          number of rays => 4
          top dimension of the cones => 2

    o2 : Fan

    i3 : F = directProduct(F1,F2)

    o3 = {ambient dimension => 3         }
          number of generating cones => 8
          number of rays => 6
          top dimension of the cones => 3

    o3 : Fan

    i4 : F == normalFan hypercube 3

    o4 = true

See also Fan * Fan.

## Ways to use this method:

- directProduct(Fan,Fan) -- computes the direct product of two fans

The source of this document is in /build/macaulay2-88fgJW/macaulay2-1.25.11+ds/M2/Macaulay2/packages/OldPolyhedra.m2:7146:0.