function Sep11()

  function I = IntSpline(S)
% S is a pp-represenattion of a spline S(x) with breakpoints
% x(1)<...<x(n). I is the integral of S from x(1) to x(n)

[x,Coeff] = unmkpp(S);
n = length(x);
I = 0;
for k=1:n-1
    % The kth local cubic is
    %     c(1)(x-x(k))^3 + c(2)(x-x(k))^2 + c(3)(x-x(k)) + c(4)
    % where
    c = Coeff(k,:);
    % The square of its second derivative is
    %     b(1)(x-x(k))^2 + b(2)(x-x(k) + b(3)
    b = 
    % The integral of of this from x(k) to x(k+1)  is
    Ik = 
    % Update running sum
    I = I + Ik;
end

 
    
