Bounding ranks of elliptic curves

The purpose of this paper is to provide a new way of approach and get a result on the rank bound problem.; We construct cohomology classes from quadratic twisted elliptic curves very similar to Kolyvagin's cohomology classes. We verify that these cohomology classes satisfy a formula for computation as was obtained by Kolyvagin.; This has an immediate consequence of $EDQ\subset EDR0$ if E and D satisfy some conditions which will be described.; The formulas from the construction, combined with mod 2 algebra, gives us a bound of rank $EQ⩽2n$ if is a PID where n is the number of prime divisors of 2N∞. Here Δ = Δ(E) is the discriminant and N is the conductor of E. This result extends our knowledge on the rank bound.