For
p
⩾
12
11
p\geqslant \frac {12}{11}
, the eigenfunctions of the non-linear eigenvalue problem for the
p
p
-Laplacian on the interval
(
0
,
1
)
(0,1)
are shown to form a Riesz basis of
L
2
(
0
,
1
)
L_2(0,1)
and a Schauder basis of
L
q
(
0
,
1
)
L_q(0,1)
whenever
1
>
q
>
∞
1>q>\infty
.