function interv=triangleint(a,b,c,n)
% this function can caculate the level cut-sets of triangle fuzzy number (b;[a,c]);
% where lamda=i/n(i=0:n) is the n+1 levels;
for i=1:n+1
    ad(i)=a+(b-a)*(i-1)/n;
    au(i)=c-(c-b)*(i-1)/n;
end
interv=[ad;au];