Re: Question about the use of mfslashexpansion

[Bill Allombert <Bill.Allombert@math.u-bordeaux.fr>]

On Mon, Aug 04, 2025 at 04:54:21PM +0000, LNU, Swati wrote:
> Hello,
> I was trying to understand the use of mfslashexpansion via the following example but it is giving me incorrect answers:
> I am trying to compute the action of eta(z)^8 * eta(2z)^8 acted by U_2 which equals -8 * q + 64 * q^2 - 96 * q^3 + .... On the other hand,
> a = mffrometaquo([1, 8; 2, 8]);
> b = mfinit(a);
> c = 8 * (mfslashexpansion(b, a, [1, 0; 0, 2], 50, 0) +  mfslashexpansion(b, a, [1, 1; 0, 2], 50, 0))
> 
> [0, 0, -8, 0, 64, 0, -96, 0, -512, 0, 1680, 0, 768, 0, -8128, 0, 4096, 0, 16344, 0, -13440, 0, -8736, 0, -6144, 0, -11056, 0, 65024, 0, 20160, 0, -32768, 0, -117648, 0, -130752, 0, 319520, 0, 107520, 0, -97536, 0, 69888, 0, -549696, 0, 49152, 0, 272200]

Why do you think the answer is incorect ?

Cheers,
Bill.