most recent 30 from http://mathoverflow.net 2013-05-24T02:34:53Z http://mathoverflow.net/feeds/user/22387 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/92119/duality-of-eta-product-identities-a-new-idea/92133#92133 A.L. 2012-03-25T04:29:38Z 2012-03-25T04:29:38Z

<p>I would guess that this is just due to the fact that taking the dual preserves the space (i.e. if P_1 and P_2 are in the same space, the duals Q_1 and Q_2 will be as well, or at least <em>some</em> same space, maybe the level goes up a bit, I can't remember) of the eta quotient, and that this space is finite dimensional. </p>