Interval boundary element method

Interval boundary element method is classical boundary element method with the interval parameters.
Boundary element method is based on the following integral equation

${\displaystyle c\cdot u=\int \limits _{\partial \Omega }\left(G{\frac {\partial u}{\partial n}}-{\frac {\partial G}{\partial n}}u\right)dS}$

The exact interval solution on the boundary can be defined in the following way:

${\displaystyle {\tilde {u}}(x)=\{u(x,p):c(p)\cdot u(p)=\int \limits _{\partial \Omega }\left(G(p){\frac {\partial u(p)}{\partial n}}-{\frac {\partial G(p)}{\partial n}}u(p)\right)dS,p\in {\hat {p}}\}}$

In practice we are interested in the smallest interval which contain the exact solution set

${\displaystyle {\hat {u}}(x)=hull\ {\tilde {u}}(x)=hull\{u(x,p):c(p)\cdot u(p)=\int \limits _{\partial \Omega }\left(G(p){\frac {\partial u(p)}{\partial n}}-{\frac {\partial G(p)}{\partial n}}u(p)\right)dS,p\in {\hat {p}}\}}$

In similar way it is possible to calculate the interval solution inside the boundary ${\displaystyle \Omega }$.