積分方程式
f ( x ) = ∫ a x K ( x , t ) φ ( t ) d t {\displaystyle f(x)=\int _{a}^{x}K(x,t)\,\phi (t)\,dt}
φ ( x ) = f ( x ) + λ ∫ a b K ( x , t ) φ ( t ) d t {\displaystyle \phi (x)=f(x)+\lambda \int _{a}^{b}K(x,t)\,\phi (t)\,dt}