# Graphs having highest second smallest laplacian eigen value from a collection

Using this code

```
for G in graphs(7):
if G.girth()==4:
L = G.laplacian_matrix().eigenvalues()
L.sort()
show(L)
G.show()
```

I have generated all graphs on $7$ vertices having girth=4. Now, from this code can we get the only unique graph having largest algebraic connectivity among all others.

What is the definition of algebraic connectivity?