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concept about function $\binom{ \infty}k$ For $ k \in \mathbb{N}$

The idea of ​​this function is derived from my power sum formula

link for my power sum formula

Formula is as

$$\sum_{k=1}^{n} k^{m}=\sum_{b=1}^{m+1} \binom{n}b\sum_{i=0}^{b-1} (-1)^{i}(b-i)^{m}\binom{b-1}i$$

This formula helps to derive $\binom{ \infty}k$ function and to calculate it's value. we know the negative values of zeta function.if

$$ \zeta(-m)=\lim_{n\to \infty}\sum_{k=1}^{n} k^{m}$$

So can we construct it as $$\zeta(-m)=\sum_{b=1}^{m+1} \binom{\infty}b\sum_{i=0}^{b-1} (-1)^{i}(b-i)^{m}\binom{b-1}i$$ Then we can calculate, if we substitute value $\zeta (0)=-1/2$ then$\binom{\infty}1=-1/2$

Again we can calculate next value using or substituting previous values of $\binom{\infty}k$.

Other values of $\binom{\infty}k$are

$$\binom{\infty}2=5/12$$ $$\binom{\infty}3=-3/8$$ $$\binom{\infty}4=251/720$$ $$...$$ And so on.

Application

Definition

Let's us define a sequence as :

$$a=(a_{1},a_{2},a_{3},...)$$

Difference between two term is as follows

$$\triangle^{0}a_{n}=a_{n}$$ $$\triangle^{1}a_{n}=a_{n+1}-a_{n}$$ More generally $$\triangle^{m}a_{n}=\triangle^{m-1}a_{n+1}-\triangle^{m-1}a_{n}$$ If there exist some $m$ for $\triangle^{m}a_{n}=0$ such that $\forall n \in \mathbb{N}$

Then $$\sum_{k=1}^{n} a_{k}=\sum_{b=1}^{m+1} \binom{n}b\triangle^{b-1}a_1$$

now if $\lim_{n \to \infty}$ put values $\binom{\infty}b$

$$\sum_{k=1}^{\infty} a_{k}=\sum_{b=1}^{m+1} \binom{\infty}b\triangle^{b-1}a_1$$

And Get the result

Example

To calculate $1+3+5+...+(2n-1)+...=1/3$

Question

Q1- how this function $\binom{\infty}k$ impact to understanding and analysis of mathematics?

<p>Q2- can we derive it's definition/algorithm to calculate  <em>function</em> <span class="math-container">$\binom{\infty}k$</span> for <span class="math-container">$k\in\mathbb{C}$</span>  values by analysis in some field , i mean what is generalization for <em>function</em> <span class="math-container">$\binom{\infty}k$</span>?</p>

<p>Q3-Is it have some interesting properties?</p>

Thank you very much for your suggestions comments and answer.

Pruthviraj
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    Is this a similar try to make something nonsensical meaningful as the "equation" $$1+2+3+4+\cdots =-1/12$$ ? – Peter Jun 19 '19 at 13:39
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    The equation $$\zeta(-m)=\lim_{n\to \infty}\sum_{k=1}^{n} k^{m}$$ is not true at all. The RHS diverges whereas the LHS is a well defined constant value. – Peter Foreman Jun 19 '19 at 13:40
  • Ok, may be i need to study more... – Pruthviraj Jun 19 '19 at 13:47
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    I wouldn't say it's necessarily illegal. Simply defining $\binom{\infty}{n}$ by an expression like $$ \zeta(-m)=\sum\binom{\infty}{n}\sum ... $$ is not strictly speaking wrong. The better question would be, do these numbers have some interesting properties? Is there any deeper way in which they are related to the standard binomial coefficients? That the answers here are in the affirmative is not at all obvious. – J_P Jun 19 '19 at 14:02
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    Pruthviraj, You might want to check out "Three ways to sum a divergent series" https://www.johndcook.com/blog/2018/09/06/sum-a-divergent-series/ – irchans Jun 19 '19 at 14:12
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    I always say: $\infty$ is a direction, not a number – gen-ℤ ready to perish Jun 19 '19 at 15:06
  • It seems legal, it has a well-defined unique value, but I wouldn´t denote it as $\binom{ \infty}k$. – Grešnik Jun 19 '19 at 19:54
  • I agree Peter Foreman. And for me, the concept given in this question makes no sense. If we arrive at equations like the example in this question it should be obvious that the concept is not actually valid. – Peter Jun 20 '19 at 07:59
  • To justify $1+2+3+4+\cdots =-1/12$ because of the zeta-function is like saying "I can buy a plane" by just ignoring not to have enough money. – Peter Jun 20 '19 at 08:05
  • Do you understand my answer ? You are doing a weird/unnatural summation method for polynomials – reuns Jun 20 '19 at 19:22
  • @reuns Yes I understand but don't know which type of algebraic rules behind it,to generalize . Yes it's weird but it satisfied us on some conditions. may be Q1&Q3 are not sharp but it interesting and important, – Pruthviraj Jun 20 '19 at 23:36

1 Answers1

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  • There is a unique polynomial $P_m(x)$ such that $P_m(0) = 0$ and $P_m(x)-P_m(x-1)= x^m$ so $P_m(n)=\sum_{k=1}^n k^m$ and you are setting $$P_m(\infty) = \zeta(-m)$$

  • For any polynomial $f(x)$ such that $f(0) = 0$ then $f(x)-f(x-1)$ is a polynomial $$f(x)-f(x-1) = \sum_{j=0}^d c_j x^j$$

    You are setting $$f(\infty) = \sum_{j=0}^d c_j \zeta(-j)$$

  • With $g_l(x) = {x \choose l}$ then $$g_l(x)-g_l(x-1) =\sum_{j=0}^{l-1} b_{l,j} x^j$$ $${\infty \choose l} =\sum_{j=0}^{l-1} b_{l,j} \zeta(-j)$$

  • From $\sum_{n=1}^N (-1)^{n+1} = \frac{1+(-1)^{N+1}}{2}$ we have that $\eta(s)=(1-2^{1-s})\zeta(s) = \sum_{n=1}^\infty (-1)^{n+1} n^{-s}$ is entire and $$\eta(-j) = \lim_{x \to 1} \sum_{n=1}^\infty (-1)^{n+1} n^j x^n$$ Let $$T (\sum_{j=0}^d c_j x^j)(x) = \sum_{j=0}^d \frac{c_j}{1-2^{1+j}} x^j$$ you are setting $$f(\infty) = \lim_{x \to 1} \sum_{n=1}^\infty (-1)^{n+1}x^n T(f(x)-f(x-1))(n) $$ The problem is that operator $T$ which makes it unobvious how to generalize your summation method to any sequences, not only polynomials.

reuns
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