Re: Labelling polyhedron faces




Axel Harvey wrote:
For example, how many ways are there to label the
faces of a regular dodecahedron with numbers n
from 0 to 11 so that (1) all pairs of faces n and n+1
share an edge; (2) face n is diametrically opposed
to face n+6 mod 12; (3) faces 11 and 0 share an
edge?

I'm not so much interested in a specific answer (I
think I can get it with a model and post-it stickers)
as in approaches to this sort of problem. I am not a
mathematician so I don't even know what general
topic it falls under.

Graph Theory. You're looking for a Hamiltonian cycle in the icosohedron
graph.

To get the other condition (n is opposite n+6), you actually want to
look at the graph H obtained from the icosohedron by identifying
opposite pairs of vertices. Then any Hamiltonian cycle of H will give
you a Hamiltonian cycle of the icosohedron where n is opposite n+6.

H might be a little difficult to describe, so I might follow up on
this. (I have to rush off and teach class.)

--- Christopher Heckman

.



Relevant Pages

  • Re: all paths between 2 nodes
    ... it is a directed graph without any directed cycles. ... >> in the opposite direction is not a path (at least not under ... orientation of the edges deals almost exclusively with network ... flow algorithms (frequently you want to push flow in the ...
    (comp.theory)
  • Re: Continued training with octahedron.
    ... I showed icosahedral graph by octahedron. ... There is Hamiltonian cycle count 2560 in the below table of link. ... this is equal to edge's cycle in octahedron. ... One ant is on a vertex of icosahedron. ...
    (sci.math)
  • Re: Continued training with octahedron.
    ... I showed icosahedral graph by octahedron. ... There is Hamiltonian cycle count 2560 in the below table of link. ... this is equal to edge's cycle in octahedron. ... One ant is on a vertex of icosahedron. ...
    (sci.math)
  • Re: Continued training with octahedron.
    ... I showed icosahedral graph by octahedron. ... There is Hamiltonian cycle count 2560 in the below table of link. ... this is equal to edge's cycle in octahedron. ... One ant is on a vertex of icosahedron. ...
    (sci.math)
  • Continued training with octahedron.
    ... I showed icosahedral graph by octahedron. ... There is Hamiltonian cycle count 2560 in the below table of link. ... this is equal to edge's cycle in octahedron. ... This ant moves on edge of octahedron. ...
    (sci.math)