Series with monotone coefficients by Walsh system

The paper studies the series $\sum\limits_{n = 0}^\infty {a_n } W_n (x)$ by Walsh system, where |a _n | monotone tends to zero and $\sum\limits_{n = 1}^\infty {a_{_n }^2 } = \infty $ . Some theorems on correction in L ¹ and representability of functions from L ^p , p ∈ (0, 1) by subseries of the Walsh series are proved.