... b]xp(s)xLp=ba|x(s)|pds1/p< +∞ (1.1)W1 2 f ∈ L 2 [a, b]f∈ L 2 [a, b]f 2 W1 2 = f 2 L 2 + f 2 L 2 < ∞xC[a,b]= maxs∈[a,b]|x(s)| (1 .2) Xxn⊂ Xx0∈ X n → ∞ xn−x0 ... ∂K/∂t•A : C[a, b] → L 2 [a, b]x(s) → f0(t) =baK(t, s)x(s)ds.L 2 [a, b]f1(t) f 2 (t) L 2 [a, b]ρL 2 [a,b](f1, f 2 ) =ba|f1(t) −f 2 (t)| 2 dt1 /2 .(1.5) x0(s)f1(t) ... AfL 2 .λj, ϕjA λ1> λ 2 > ϕj∈ Aϕj(s) = AUs, ϕjL 2 = λjUs, ϕjL 2 1 = ϕj, ϕjL 2 = λjUs, ϕjL 2 , ϕj(s)L 2 .UsL 2 ≥Us, ϕjL 2 ,...