A357592 Number of edges of the Minkowski sum of n simplices with vertices e_(i+1), e_(i+2), e_(i+3) for i=0,...,n-1, where e_i is a standard basis vector.

3, 11, 34, 96, 260, 683, 1757, 4447, 11114, 27493

Offset: 1

Author

Alejandro H. Morales, Oct 05 2022

Keywords

• nonn
• hard
• more

Links

• L. Escobar, P. Gallardo, J. González-Anaya, J. L. González, G. Montúfar, and A. H. Morales, Enumeration of max-pooling responses with generalized permutohedra, arXiv:2209.14978 [math.CO], 2022. (See Table 2)

Crossrefs

Cf. A033303, A007070.

Programs

Sage

def a(n): return len(PP(n,3,1).graph().edges())
def Delta(I,n):
    IM = identity_matrix(n)
    return Polyhedron(vertices=[IM[e] for e in I],backend='normaliz')
def Py(n,SL,yL):
    return sum(yL[i]*Delta(SL[i],n) for i in range(len(SL)))
def PP(n,k,s):
    SS = [set(range(s*i,k+s*i)) for i in range(n)],[1,]*(n)
    return Py(s*(n-1)+k,SS[0],SS[1])
[a(n) for n in range(1,4)]