Missing Fourier coefficients for Siegel modular forms

[jwj61]

From the feedback page about the page http://www.lmfdb.org/ModularForm/GSp/Q/Sp4Z.10_Maass/?ev_index=&modulus=&fc_det=4

Some Fourier coefficients of Siegel modular forms are missing, or the phrase 'c(F) available for det(F) in ...' is misleading. For instance, in the URL above, the coefficient (2,2,1) : -2 is not listed. Similar issues occur for the Eisenstein series 4_E and 6_E (which are the only ones I have looked into). Therefore, if the user attemps to reconstruct the beginning of the Fourier development from the LMFDB, he must:

• understand that (i,j,k) denotes the matrix (2i, j; j, 2k) (this is not documented)
• take symmetrization (i,j,k) -> (k,j,i) and (i,j,k) -> (i,-j,k) into account (this is not documented, and the second one is easily forgotten) and even then the development will not be correct due to missing coefficients.

Reply to jean.kieffer@math.u-bordeaux.fr

[AndrewVSutherland]

The Siegel modular forms section of the LMFDB was reverted to beta in November (for this and other reasons) and is no longer visible on the production postgres branch (see web.lmfdb.xyz). As soon as we switch www.lmfdb.org to point to web.lmfdb.xyz (hopefully by the end of this month) Siegel modular forms will no longer be visible.

This issue still needs to be addressed, but I think this should be done as part of a comprehensive treatment of Siegel modular forms which likely won't happen until next year -- fixing things piecemeal is not a productive use of our time in situation like this where we know we want to rethink the entire presentation/content of this part of the LMFDB.

But if anyone is motivated to fix this, by all means, go for it!.