The Prenucleolus: 

x1 = 4
x2 = 4
x3 = 3
x4 = 3

Excesses:

0 ()
-8.88178e-16 (2 4 )
-1e-06 (1 3 )
-1e-06 (1 2 3 4 )
-3 (4 )
-3 (1 2 )
-3 (3 )
-3 (2 3 4 )
-3 (1 3 4 )
-4 (1 )
-4 (2 )
-4 (1 2 4 )
-4 (1 2 3 )
-6 (3 4 )
-7 (1 4 )
-7 (2 3 )