# Notes for users of other computer algebra systems

## General differences

• TODO: $2^{100}$ is evaluated to 0; write $fmpz(2)^100$ to get a long

## Notes for GAP users

• TODO
• TODO: also talk about how to use it from OSCAR?

## Notes for Singular users

• TODO
• TODO: also talk about how to use it from OSCAR?

## Notes for Polymake users

• OSCAR (and Julia) is 1-based, meaning that it counts from 1, rather than from 0 like polymake. For most properties we have taken care of the translation but be aware that it might pop up at some point and generate confusion.

For convenience, Polymake.jl provides Polymake.to_one_based_indexing and Polymake.to_zero_based_indexing.

• Polyhedra and polyhedral complexes in OSCAR are represented inhomogeneously, i.e. without the leading 1 for vertices or 0 for rays. Hence constructors take points, rays, and lineality generators separately.

• user_methods cannot be accessed via Julia's dot syntax, i.e. something like

c = Polymake.polytope.cube(3)
c.AMBIENT_DIM

will not work. Instead user_methods are attached as Julia functions in their respective application. They are always written in lowercase. In the example the following works:

c = Polymake.polytope.cube(3)
Polymake.polytope.ambient_dim(c)

• TODO

• TODO