1. The problem statement, all variables and given/known data http://img219.imageshack.us/img219/2512/60637341vi6.png [Broken] 2. Relevant equations I think this is relevant: http://img505.imageshack.us/img505/336/51636887dc4.png [Broken] 3. The attempt at a solution A topological isomorphism implies that T and T-1 are bounded and given is that all cauchy sequences in E are convergent. But if that's the case then by boundedness all convergent sequences are bounded in het norm of F and are thus also Cauchy seqeunces. Am I thinking in the right direction?