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71 votes
8 answers
12k views

Possible new series for $\pi$

In a recent (unfortunately over-hyped) preprint by Saha and Sinha, Field theory expansions of string theory amplitudes (arXiv:2401.05733), they present the following series for $\pi$: $$\pi = 4 + \...
Timothy Chow's user avatar
  • 82.7k
5 votes
1 answer
456 views

Number defined by a recursive binary sequence

In a math column in Scientific American many years ago, I encountered a peculiar binary sequence I describe below. Unfortunately I can't find a reference on this, so I would be grateful for any ...
Dominic van der Zypen's user avatar
9 votes
1 answer
638 views

Algebraic independence of $P,Q,R$ or $E_2,E_4,E_6$ over $\mathbb C(z)$

Let $P,Q,R$ be the Fourier series of the Eisenstein series $E_2,E_4,E_6$, that is, $$ P(q)=1-24\sum_{n=1}^{\infty}\sigma_1(n)q^n, $$ $$ Q(q)=1+240\sum_{n=1}^{\infty}\sigma_3(n)q^n, $$ $$ R(q)=1-504\...
LWW's user avatar
  • 663
5 votes
1 answer
235 views

Algebraic independence of $a^a$ and $b^b$ for algebraic irrationals $a,b$

Let $a,b$ be algebraic irrationals. Are there conjectures or unconditional results about the algebraic independence of $a^a$ and $b^b$? Probably Schanuel's conjecture is related, maybe only $\log{a},...
joro's user avatar
  • 25.4k
14 votes
1 answer
1k views

Transcendence of $\Gamma(1/3), \Gamma(1/4)$

This is a re-post from MSE as I did not get even a single comment there. Wikipedia mentions that the transcendence of $\Gamma(1/3), \Gamma(1/4)$ was proved by G. V. Chudnovsky. Does anyone have a ...
Paramanand Singh's user avatar
3 votes
0 answers
454 views

What is the relation between the length of period of simple continued fraction expansion of quadratic algebraic numbers $\sqrt{A}$ and the integer $A$

What is the relation between the length of period of simple continued fraction expansion of quadratic algebraic numbers and the integer As we know,$\sqrt{2} = [1;2,2,2,2,…]$; while $\sqrt{14}= [3;1,2,...
XL _At_Here_There's user avatar
0 votes
0 answers
234 views

On the irrationality measure of generalized Stoneham numbers

Pick non-zero integers $a,b,c$ with $a,b \ge 2$ and let $\xi_{a,b,c}$ be the sum of the series $\sum_{n=1}^\infty a^{-b^n} c^{-n}$ (no restriction is made on the sign of $c$); when $b = c$ and $\gcd(a,...
Salvo Tringali's user avatar
8 votes
1 answer
620 views

On the irrationality measure of $\sum_{n=1}^\infty a^{-b^n}$

Pick integers $a, b \ge 2$ and let $\xi_{a,b}$ be the sum of the series $\sum_{n=1}^\infty a^{-b^n}$. It is known that $\xi_{2,2}$ is transcendental: I learned a proof of this from notes by M. ...
Salvo Tringali's user avatar
19 votes
1 answer
2k views

"The Galois group of $\pi$ is $\mathbb{Z}$."

Last year, in a talk of Michel Waldschmidt's, I remember hearing a statement along the lines of the title of this question, that is, "The Galois group of $\pi$ is $\mathbb{Z}$.". In what sense/...
Joshua Seaton's user avatar