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Identifier
Values
=>
Cc0020;cc-rep
([],1)=>1 ([],2)=>2 ([(0,1)],2)=>1 ([],3)=>3 ([(1,2)],3)=>2 ([(0,2),(1,2)],3)=>1 ([(0,1),(0,2),(1,2)],3)=>0 ([],4)=>4 ([(2,3)],4)=>3 ([(1,3),(2,3)],4)=>2 ([(0,3),(1,3),(2,3)],4)=>1 ([(0,3),(1,2)],4)=>2 ([(0,3),(1,2),(2,3)],4)=>1 ([(1,2),(1,3),(2,3)],4)=>1 ([(0,3),(1,2),(1,3),(2,3)],4)=>0 ([(0,2),(0,3),(1,2),(1,3)],4)=>0 ([(0,2),(0,3),(1,2),(1,3),(2,3)],4)=>-1 ([(0,1),(0,2),(0,3),(1,2),(1,3),(2,3)],4)=>-2 ([],5)=>5 ([(3,4)],5)=>4 ([(2,4),(3,4)],5)=>3 ([(1,4),(2,4),(3,4)],5)=>2 ([(0,4),(1,4),(2,4),(3,4)],5)=>1 ([(1,4),(2,3)],5)=>3 ([(1,4),(2,3),(3,4)],5)=>2 ([(0,1),(2,4),(3,4)],5)=>2 ([(2,3),(2,4),(3,4)],5)=>2 ([(0,4),(1,4),(2,3),(3,4)],5)=>1 ([(1,4),(2,3),(2,4),(3,4)],5)=>1 ([(0,4),(1,4),(2,3),(2,4),(3,4)],5)=>0 ([(1,3),(1,4),(2,3),(2,4)],5)=>1 ([(0,4),(1,2),(1,3),(2,4),(3,4)],5)=>0 ([(1,3),(1,4),(2,3),(2,4),(3,4)],5)=>0 ([(0,4),(1,3),(2,3),(2,4),(3,4)],5)=>0 ([(0,4),(1,3),(1,4),(2,3),(2,4),(3,4)],5)=>-1 ([(0,3),(0,4),(1,3),(1,4),(2,3),(2,4)],5)=>-1 ([(0,3),(0,4),(1,3),(1,4),(2,3),(2,4),(3,4)],5)=>-2 ([(0,4),(1,3),(2,3),(2,4)],5)=>1 ([(0,1),(2,3),(2,4),(3,4)],5)=>1 ([(0,3),(1,2),(1,4),(2,4),(3,4)],5)=>0 ([(0,3),(0,4),(1,2),(1,4),(2,4),(3,4)],5)=>-1 ([(0,3),(0,4),(1,2),(1,4),(2,3)],5)=>0 ([(0,1),(0,4),(1,3),(2,3),(2,4),(3,4)],5)=>-1 ([(0,3),(0,4),(1,2),(1,4),(2,3),(2,4),(3,4)],5)=>-2 ([(0,4),(1,2),(1,3),(2,3),(2,4),(3,4)],5)=>-1 ([(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5)=>-1 ([(0,4),(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5)=>-2 ([(0,3),(0,4),(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5)=>-3 ([(0,3),(0,4),(1,2),(1,3),(1,4),(2,3),(2,4)],5)=>-2 ([(0,2),(0,3),(0,4),(1,2),(1,3),(1,4),(2,4),(3,4)],5)=>-3 ([(0,2),(0,3),(0,4),(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5)=>-4 ([(0,1),(0,2),(0,3),(0,4),(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5)=>-5 ([],6)=>6 ([(4,5)],6)=>5 ([(3,5),(4,5)],6)=>4 ([(2,5),(3,5),(4,5)],6)=>3 ([(1,5),(2,5),(3,5),(4,5)],6)=>2 ([(0,5),(1,5),(2,5),(3,5),(4,5)],6)=>1 ([(2,5),(3,4)],6)=>4 ([(2,5),(3,4),(4,5)],6)=>3 ([(1,2),(3,5),(4,5)],6)=>3 ([(3,4),(3,5),(4,5)],6)=>3 ([(1,5),(2,5),(3,4),(4,5)],6)=>2 ([(0,1),(2,5),(3,5),(4,5)],6)=>2 ([(2,5),(3,4),(3,5),(4,5)],6)=>2 ([(0,5),(1,5),(2,5),(3,4),(4,5)],6)=>1 ([(1,5),(2,5),(3,4),(3,5),(4,5)],6)=>1 ([(0,5),(1,5),(2,5),(3,4),(3,5),(4,5)],6)=>0 ([(2,4),(2,5),(3,4),(3,5)],6)=>2 ([(0,5),(1,5),(2,4),(3,4)],6)=>2 ([(1,5),(2,3),(2,4),(3,5),(4,5)],6)=>1 ([(0,5),(1,5),(2,3),(3,4),(4,5)],6)=>1 ([(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>1 ([(1,5),(2,4),(3,4),(3,5),(4,5)],6)=>1 ([(0,5),(1,5),(2,4),(3,4),(4,5)],6)=>1 ([(0,5),(1,5),(2,3),(2,4),(3,5),(4,5)],6)=>0 ([(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>0 ([(0,5),(1,5),(2,4),(3,4),(3,5),(4,5)],6)=>0 ([(0,5),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-1 ([(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6)=>0 ([(0,5),(1,4),(2,4),(2,5),(3,4),(3,5)],6)=>0 ([(0,5),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6)=>-1 ([(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-1 ([(0,5),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-1 ([(0,5),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-2 ([(0,4),(0,5),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6)=>-2 ([(0,4),(0,5),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-3 ([(0,5),(1,4),(2,3)],6)=>3 ([(1,5),(2,4),(3,4),(3,5)],6)=>2 ([(0,1),(2,5),(3,4),(4,5)],6)=>2 ([(1,2),(3,4),(3,5),(4,5)],6)=>2 ([(0,5),(1,4),(2,3),(3,5),(4,5)],6)=>1 ([(1,4),(2,3),(2,5),(3,5),(4,5)],6)=>1 ([(0,1),(2,5),(3,4),(3,5),(4,5)],6)=>1 ([(0,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6)=>0 ([(1,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6)=>0 ([(0,5),(1,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6)=>-1 ([(1,4),(1,5),(2,3),(2,5),(3,4)],6)=>1 ([(0,5),(1,4),(2,3),(2,4),(3,5),(4,5)],6)=>0 ([(1,2),(1,5),(2,4),(3,4),(3,5),(4,5)],6)=>0 ([(0,5),(1,2),(1,4),(2,3),(3,5),(4,5)],6)=>0 ([(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6)=>0 ([(0,5),(1,4),(2,3),(3,4),(3,5),(4,5)],6)=>0 ([(0,5),(1,2),(1,5),(2,4),(3,4),(3,5),(4,5)],6)=>-1 ([(0,5),(1,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-1 ([(1,4),(1,5),(2,3),(2,5),(3,4),(3,5),(4,5)],6)=>-1 ([(0,5),(1,4),(1,5),(2,3),(2,5),(3,4),(3,5),(4,5)],6)=>-2 ([(0,5),(1,4),(2,3),(2,4),(3,5)],6)=>1 ([(0,1),(2,4),(2,5),(3,4),(3,5)],6)=>1 ([(0,5),(1,5),(2,3),(2,4),(3,4)],6)=>1 ([(0,4),(1,2),(1,3),(2,5),(3,5),(4,5)],6)=>0 ([(0,4),(1,2),(1,5),(2,5),(3,4),(3,5)],6)=>0 ([(0,4),(1,2),(2,5),(3,4),(3,5),(4,5)],6)=>0 ([(0,1),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>0 ([(0,4),(1,4),(2,3),(2,5),(3,5),(4,5)],6)=>0 ([(0,3),(0,4),(1,2),(1,5),(2,5),(3,5),(4,5)],6)=>-1 ([(0,3),(1,4),(1,5),(2,4),(2,5),(3,5),(4,5)],6)=>-1 ([(0,4),(1,2),(1,5),(2,5),(3,4),(3,5),(4,5)],6)=>-1 ([(0,1),(0,5),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-2 ([(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>0 ([(0,5),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6)=>-1 ([(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-1 ([(0,5),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-2 ([(0,1),(0,5),(1,4),(2,4),(2,5),(3,4),(3,5)],6)=>-1 ([(0,3),(0,5),(1,3),(1,5),(2,4),(2,5),(3,4),(4,5)],6)=>-2 ([(0,3),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-2 ([(0,5),(1,4),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6)=>-2 ([(0,1),(0,5),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-2 ([(0,4),(0,5),(1,4),(1,5),(2,3),(2,5),(3,4),(3,5),(4,5)],6)=>-3 ([(0,5),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6)=>-2 ([(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-2 ([(0,5),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-2 ([(0,5),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-3 ([(0,4),(0,5),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6)=>-3 ([(0,4),(0,5),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-4 ([(0,5),(1,3),(1,4),(2,3),(2,4),(3,5),(4,5)],6)=>-1 ([(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6)=>-1 ([(0,5),(1,3),(1,4),(2,3),(2,4),(2,5),(3,5),(4,5)],6)=>-2 ([(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6)=>-2 ([(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6)=>-3 ([(0,4),(0,5),(1,2),(1,3),(2,5),(3,4)],6)=>0 ([(0,3),(0,5),(1,2),(1,5),(2,4),(3,4),(4,5)],6)=>-1 ([(0,5),(1,2),(1,4),(2,3),(3,4),(3,5),(4,5)],6)=>-1 ([(0,1),(0,2),(1,5),(2,4),(3,4),(3,5),(4,5)],6)=>-1 ([(0,5),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5)],6)=>-1 ([(0,5),(1,3),(1,4),(2,4),(2,5),(3,4),(3,5)],6)=>-1 ([(0,1),(0,5),(1,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-2 ([(0,4),(1,3),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6)=>-2 ([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(3,5),(4,5)],6)=>-2 ([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6)=>-3 ([(0,4),(0,5),(1,2),(1,3),(2,4),(2,5),(3,4),(3,5)],6)=>-2 ([(0,5),(1,2),(1,3),(1,4),(2,3),(2,4),(3,5),(4,5)],6)=>-2 ([(0,4),(0,5),(1,2),(1,3),(1,5),(2,4),(2,5),(3,4),(3,5)],6)=>-3 ([(0,4),(0,5),(1,2),(1,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-3 ([(0,4),(0,5),(1,2),(1,3),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-4 ([(0,5),(1,2),(1,3),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-3 ([(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-3 ([(0,5),(1,3),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-3 ([(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-4 ([(0,4),(0,5),(1,2),(1,4),(2,3),(2,5),(3,4),(3,5),(4,5)],6)=>-3 ([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6)=>-3 ([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-4 ([(0,4),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-5 ([(0,3),(0,4),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5)],6)=>-3 ([(0,1),(0,2),(0,3),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-4 ([(0,4),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6)=>-4 ([(0,3),(0,4),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6)=>-5 ([(0,3),(0,4),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-6 ([(0,4),(0,5),(1,2),(1,3),(2,3),(4,5)],6)=>0 ([(0,2),(1,4),(1,5),(2,3),(3,4),(3,5),(4,5)],6)=>-1 ([(0,1),(0,5),(1,5),(2,3),(2,4),(3,4),(4,5)],6)=>-1 ([(0,1),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-1 ([(0,1),(0,5),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6)=>-2 ([(0,1),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-2 ([(0,1),(0,5),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-3 ([(0,4),(0,5),(1,2),(1,3),(2,3),(2,5),(3,4),(4,5)],6)=>-2 ([(0,4),(0,5),(1,2),(1,3),(1,4),(2,3),(2,5),(3,5),(4,5)],6)=>-3 ([(0,3),(1,2),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-3 ([(0,3),(0,5),(1,2),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-3 ([(0,1),(0,5),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-3 ([(0,3),(0,5),(1,2),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-4 ([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6)=>-4 ([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-5 ([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(2,5),(3,4)],6)=>-2 ([(0,1),(0,5),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5)],6)=>-2 ([(0,3),(0,4),(1,2),(1,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6)=>-3 ([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6)=>-4 ([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,3),(2,5),(3,4)],6)=>-3 ([(0,1),(0,3),(0,5),(1,2),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-4 ([(0,4),(0,5),(1,2),(1,3),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6)=>-4 ([(0,1),(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-5 ([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-6 ([(0,2),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6)=>-4 ([(0,4),(0,5),(1,2),(1,3),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-4 ([(0,4),(0,5),(1,2),(1,3),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-5 ([(0,5),(1,2),(1,3),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-4 ([(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-4 ([(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-5 ([(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-6 ([(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-7 ([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6)=>-5 ([(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6)=>-5 ([(0,1),(0,4),(0,5),(1,2),(1,3),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-5 ([(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6)=>-6 ([(0,2),(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6)=>-6 ([(0,2),(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-7 ([(0,2),(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-8 ([(0,1),(0,2),(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6)=>-9
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Description
The Euler characteristic of a graph.
The Euler characteristic $\chi$ of a topological space is the alternating sum of the dimensions of the homology groups
$$\chi(X) = \sum_{k \geq 0} (-1)^k \dim H_k(X).$$
For a finite simplicial complex, this is equal to the alternating sum $ \sum_{k\geq 0} (-1)^k f_k$ where $f_k$ the number of $k$-dimensional simplices. A (simple) graph is a simplicial complex of dimension at most one; its vertices are the 0-simplices and its edges are the 1-simplices.
For a connected graph, the Euler characteristic is equal to $1 - g$ where $g$ is the cyclomatic number.
References
[1] wikipedia:Euler_characteristic
[2] The cyclomatic number of a graph. St001311
Code
def statistic(g):
    return g.num_verts() - g.num_edges()
Created
Jul 27, 2022 at 13:04 by Harry Richman
Updated
Jul 27, 2022 at 13:04 by Harry Richman