trying to do some maths in Maxima, it is telling me "if a < 0 then b else if a = 0 then b else if a > 0 then b". b is my original input that I'm trying to get it to expand/rearrange. this is not useful. it shouldn't matter if it's even real or not, is just rearranging algebra (bivariate series)

got something to expand by limiting summation ranges to 3 instead of \infty. would have been nicer to get summations with binomial coefficients or what have you. this is an expansion of something done to $\sum{i,j} a_{i,j} c^i z^j$, and I want to collect up all the powers and find expressions for the new $a_{i,j}$ in terms of the previous ones. maybe I should try some other software, maxima is a pain

That expression is for A_n → A_{n+1}, which I already have code for (thanks to knighty) but what I'm really after today is something for A_n → A_{2n}.

Suppose
$$ A_n(c,z) = \sum a_{n,i,j} c^i z^j $$ and
$$ A_{2n} = A_n(c, A_n(c, z)) $$
find expressions for
$$ a_{2n,i,j} $$
in terms of
$$ a_{n,i,j} $$

Follow

nevermind. that approach violates the precondition that z (as argument to the outer A_n) is small when n is not a multiple of the periodic return to 0.

I think I want something more like $A_n(c, B_m(c, z))$ but I can't figure out if the order of A and B is conducive to what I'm trying to do... I don't think it commutes.

Sign in to participate in the conversation
post.lurk.org

Hometown is adapted from Mastodon, a decentralized social network with no ads, no corporate surveillance, and ethical design.