Non-Associativity of Lorentz Transformation and Associative Reflection Symmetric Transformation

Each of the two moving observers observes the relative velocity of the other. The two velocities should be equal and opposite. We have shown that this relativistic requirement is not fulfilled by Lorentz transformation. We have also shown that the reason is that Lorentz transformation is not associative. Reciprocal symmetric transformation is associative and fulfills relativistic requirements.