#powerseries

N-gated Hacker Newsngate
2025-06-02

๐Ÿ“ˆ So you thought you could dodge with a โ€œconceptualโ€ take on Euler's formula? ๐Ÿ˜‚ Spoiler: it's just a fancy way to say you're still drowning in power series, but now with extra philosophy! ๐Ÿง ๐Ÿ”„
deaneyang.com//blog/blog/math/

Markus Redekermrdk@mathstodon.xyz
2024-03-16

The integral

\[ \int_0^\infty x^k e^{-x} dx = k! \]

is used as motivation for the gamma function and in the irrationality proof of \( e \). But it can also be used for the transformation \( T \) defined by

\[ T f = \int_0^\infty f(x) e^{-x} dx. \]

If \( f = \sum_i f_i x^i \) is a power series and everything converges, it is transformed to \( T f = \sum_i f_i i! \). One can therefore say that \( T \) evaluates \( f \) at the factorial and write

\[ T f = f(!). \]

Are there other unusual places at which one can evaluate a function?

#Mathematics #PowerSeries #Integrals

2022-11-10

Two must reads for anyone serious about sequences, computing methodologies, and combinatorial algorithms.

S. Yurkevich, The art of algorithmic guessing in gfun,
doi.org/10.5206/mt.v2i1.14421

B. T. Tabuguia, W. Koepf, On the Rep. of Non-Holonomic Univariate Power Series,
doi.org/10.5206/mt.v2i1.14315

The examples are primarily aimed at Maple users but the expositions are general enough to give a good start.

#TheArtOfGuessing, #P-recursive sequences, #D-finite functions, #Holonomic, #PowerSeries

2020-11-22

For an insurance company to be successful over T, earning >claim , e> c
What premium { q} over T
-> {C=\Sigma X_{i}} < Nq} This large deviations theory i.i.d. random variables, where rate function is expressed as a #powerseries

2020-11-22

For an insurance company to be successful over T, earning >claim , e> c
What premium { q} over T
-> {C=\Sigma X_{i}} < Nq} This large deviations theory i.i.d. random variables, where rate function is expressed as a #powerseries

2020-11-21

complex analytic function is defined in an open ball B around a point x_0, its #powerseries expansion at x_0 is convergent in whole open ball (holomorphic functions are analytic) (1)
For real analytic functions (B : open interval of real line r/t an open disk of complex plane)

2020-11-21

complex analytic function is defined in an open ball B around a point x_0, its #powerseries expansion at x_0 is convergent in whole open ball (holomorphic functions are analytic) (1)
For real analytic functions (B : open interval of real line r/t an open disk of complex plane)

Client Info

Server: https://mastodon.social
Version: 2025.07
Repository: https://github.com/cyevgeniy/lmst