Matrix t2*K(2) in Subspace 64 with Dimension 10

(K(2) is the second-order Grosse operator)

-5*t*U 0 -(Sqrt[2]*U^2) 2*Sqrt[2]*t*U 0 0 -(t*U) Sqrt[2]*t*U 0 0
0 (-9*t*U)/2 (3*t*U)/Sqrt[2] -2*Sqrt[2]*t^2 -((4*t^2 + U^2)/Sqrt[2]) (t*U)/Sqrt[2] 4*t^2 0 Sqrt[2]*t*U -(t*U)
-(Sqrt[2]*U^2) (3*t*U)/Sqrt[2] -3*t*U -U^2 0 t*U 0 0 2*t*U Sqrt[2]*t*U
2*Sqrt[2]*t*U -2*Sqrt[2]*t^2 -U^2 -9*t*U t*U -2*t^2 -(Sqrt[2]*t*U) -2*t*U 2*t^2 0
0 -((4*t^2 + U^2)/Sqrt[2]) 0 t*U -4*t*U -2*t^2 (t*U)/Sqrt[2] t*U 2*t^2 0
0 (t*U)/Sqrt[2] t*U -2*t^2 -2*t^2 -5*t*U (4*t^2 + U^2)/Sqrt[2] 0 t*U 0
-(t*U) 4*t^2 0 -(Sqrt[2]*t*U) (t*U)/Sqrt[2] (4*t^2 + U^2)/Sqrt[2] (-9*t*U)/2 (-3*t*U)/Sqrt[2] -2*Sqrt[2]*t^2 0
Sqrt[2]*t*U 0 0 -2*t*U t*U 0 (-3*t*U)/Sqrt[2] -6*t*U -U^2 Sqrt[2]*U^2
0 Sqrt[2]*t*U 2*t*U 2*t^2 2*t^2 t*U -2*Sqrt[2]*t^2 -U^2 0 2*Sqrt[2]*t*U
0 -(t*U) Sqrt[2]*t*U 0 0 0 0 Sqrt[2]*U^2 2*Sqrt[2]*t*U -4*t*U