Classification of Quantum Hall Universality Classes by $\ W_{1+\infty}\ $ symmetry

We show how two-dimensional incompressible quantum fluids and their excitations can be viewed as $\ W_{1+\infty}\$ edge conformal field theories, thereby providing an algebraic characterization of incompressibility. The Kac-Radul representation theory of the $\ W_{1+\infty}\$ algebra leads then to a purely algebraic complete classification of hierarchical quantum Hall states, which encompasses all measured fractions. Spin-polarized electrons in single-layer devices can only have Abelian anyon excitations.Comment: 11 pages, RevTeX 3.0, MPI-Ph/93-75 DFTT 65/9

Concrete repair technology - a revised approach is needed

Just as walking is but a succession of interrupted falls, the entire history of human progress is asuccession ofstumbling half-truths and misinterpreted facts. The 'accepted facts' of today become the'recognized fallacies' oftomorrow. "Tout comme la marche n?est qu?une succession de chutes interrompues, l?histoire enti\ue8re de l?avancement de l?humanit\ue9 est une simple succession de demi-v\ue9rit\ue9s h\ue9sitantes et de faits mal interpr\ue9t\ue9s. Les \uab faits accept\ue9s \ubb d?aujourd?hui deviennent les sophismes reconnus de demain.Peer reviewed: YesNRC publication: Ye