Hey folks, Can somone explain what is meant by a 'sector' in string theory, or provide links/refs. I've tried a search on google and xxx.lanl.gov but nothing very useful turns up. Also, what is the N-S N-S sector (I know it stands for Neveu Schwarz). I think its a description of fermions that are periodic / anti periodic on a closed string, is this about right?? Any help appreciated!