how to calculate integration with limited condition at upper limit and lower limit

I want to solve a maxium of integration ' max( quad(x-v,Ei,Eg) ) ' where Eg=0.5:.05:1.3 , 0<Ei<Eg , 0<v<Ei , here is my code :

Eg=0.5:0.05:1.3 ; 
Ei=arrayfun(@(x)0:.05:x-.05,Eg,'un',0) ;

y = zeros(numel(Eg),1);

for j1 = 1:numel(Eg);

      a = arrayfun(@(ei)quad( @(x)x,ei,Eg(j1)),Ei{j1}) ;

      y(j1) = max(b);

end

I try to add an ' v ' but I dont know what can I do . thx :)