# Revision history [back]

### From the following collection how to find only those graphs having only integer eigenvalu

for g in graphs.nauty_geng("8 -c"):

g.show()

h = g.laplacian_matrix().eigenvalues()

h.sort()

show(h)

I am trying to extract those graphs having all laplacian eigenvalues are integer. But How I can filter the remaining graphs.

### From the following collection how to find only those graphs having only integer eigenvalu

for g in graphs.nauty_geng("8 -c"):

g.show()

h = g.laplacian_matrix().eigenvalues()

h.sort()

show(h)

I am trying to extract those graphs having all laplacian eigenvalues are integer. But How I can filter the remaining graphs.do this in sage?

### From the following collection how to find only those graphs having only integer eigenvalu

for g in graphs.nauty_geng("8 -c"):

g.show()

h = g.laplacian_matrix().eigenvalues()

h.sort()

show(h)

I am trying to extract those graphs having all laplacian eigenvalues are integer. How I can do this in sage?

### From the following collection how to find only those graphs having only integer eigenvalu

for g in graphs.nauty_geng("8 -c"):

g.show()

h = g.laplacian_matrix().eigenvalues()

h.sort()

show(h)

I am trying to extract those graphs having all laplacian eigenvalues are integer. How I can do this in sage?

### From the following collection how to find only those graphs having only integer eigenvalu

for g in graphs.nauty_geng("8 -c"):

g.show()

h = g.laplacian_matrix().eigenvalues()

h.sort()

show(h)

I am trying to extract those graphs having all laplacian eigenvalues are integer. How I can do Is it possible to solve this problem in sage?

### From the following collection how to find only those graphs having only integer eigenvalu

for g in graphs.nauty_geng("8 -c"):

g.show()

h = g.laplacian_matrix().eigenvalues()

h.sort()

show(h)

I am trying to extract those graphs having all laplacian eigenvalues are integer. Is it possible to solve this problem in sage?