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D.15.25.4 CoverMult
Procedure from library tropicalEllipticCovers.lib (see tropicalEllipticCovers_lib).
- Usage:
- CoverMult(G,aa,O,t[, l]); G graph, aa list, O list, t int, l list
- Assume:
- G is a Feynman graph, aa is a partition of the degree of the graph G, O is a
given ordering of the vertices of G, l is a list of leaks of G and t is some integer between 0 and 3.
- Return:
- list.
- Theory:
- For a given ordering of the vertices of G, this function computes a list of
multiplicity for each cover of G. Each entry in the list is a multiplicity of
a cover of G.
(For t=0, we get the results for simply ramified covers [BBM]. t=1, 2 we get results
for graphs w/o vertex contributions respectively w/ vertex contributions as in [BGM1],
and for t=3 we get the results for pearl chains as in [BGM2])
Example:
| | LIB "tropicalEllipticCovers.lib";
ring r=0, (x1,x2,x3,x4),dp;
graph G=makeGraph(list(1,2,3,4),list(list(1,3),list(1,2),list(1,2),list(2,4),list(3,4),list(3,4)));
CoverMult(G,list(0,2,1,0,0,1), list(x2,x4,x3,x1),0);
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