function a=sist(A,B,Z,C,D,U)
  %dice se un sistema
  % A B trasposta(lambda mu) <= Z 
  % C D trasposta(lambda mu)>= U
  % risolubile con lambda mu >=0 con A B C D Z U colonne

  p=size(A,1)
  
  a=1;

  for i=1:p
	  if B(i)>=0 & Z(i)<0
	  a=0;
	  return
	  end
	  end


	  for i=1:p
		  for j=1:p
			  if B(i)>0 & B(j)<0 & B(i)*Z(j)<B(j)*Z(i)
			  a=0;
			  return
			  end
			  end
			  end

       for i=1:p
	    for r=1:p
    		  if A(i)*D(r)-B(i)*C(r)<=0 & A(i)*U(r)-C(r)*Z(i)>0
		    a=0;
					  return
					  end
					  end
					  end
					  
			  
          for i=1:p
	      for j=1:p
		    for r=1:p
		         for s=1:p
				 if  A(i)*D(r)-B(i)*C(r)<0 & A(j)*D(s)-B(j)*C(s)>0 & (A(i)*D(r)-B(i)*C(r))*(A(j)*U(s)-C(s)*Z(j))<(A(j)*D(s)-B(j)*C(s))*(A(i)*U(r)-C(r)*Z(i))
				 a=0;
				 return
end
				 end
				 end
				 end
				 end


    for i=1:p
    for j=1:p
    for r=1:p
	     if B(j)<0 & A(i)*D(r)-B(i)*C(r)<0 & Z(j)*(A(i)*D(r)-B(i)*C(r))>B(j)*(A(i)*U(r)-C(r)*Z(i))
	    a=0;
	     return
end
end
end									       
end
	     
    for i=1:p                                                                                      
    for j=1:p                                                                                      
         for r=1:p                                                                                 
      if B(j)>0 & A(i)*D(r)-B(i)*C(r)>0 & Z(j)*(A(i)*D(r)-B(i)*C(r))<B(j)*(A(i)*U(r)-C(r)*Z(i))
		 a=0;
return                                                                                             
       end
end                                                                                                
     end                                                                                           
    end