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Questions tagged [summation-by-parts]

Summation by parts for discrete variables is the equivalent of integration by parts for continuous variables.

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1 answer
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The following inequality I found on an inequalities cheat sheet should follow from summation by parts, according to my search: if $b_1\ge b_2\ge\ldots\ge b_n\ge 0$, then $\sum_{k=1}^na_kb_k\ge b_1\...
xyz's user avatar
  • 1,390
1 vote
1 answer
147 views

I'm trying to use the specific form of Abel's sum formula: $\sum_{n \leqslant x} a_n f(n) = A(x)f(x) - \int_1^x A(t)f'(t)\,dt$ where $A(x) = \sum_{n \leqslant x} a_n$ for the following example: $A(x)=\...
onepound's user avatar
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2 votes
0 answers
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Edit: my post was marked as a duplicate of this post. The answers to this post are not related to what I'm asking. I am not looking to use the Cauchy-Schwarz inequality, as I mentioned in my post. I'm ...
stackoverflowuser's user avatar
2 votes
0 answers
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$\textbf{Question}$: Let $\{z_n\}_{n=1}^{\infty}$ be any complex series while $\sum\limits_{n=1}^{\infty}\left|z_{n+1}^{-1}-z_n^{-1}\right|=\infty$, suppose $\sum\limits_{n=1}^{\infty}a_n z_n$ is ...
George Lin's user avatar
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Let $\chi$ be a Dirichlet character modulo $q$, and consider the Dirichlet series $$L(s,\chi) = \sum_n \frac{\chi(n)}{n^s}$$ We know that $\sum_{k < n} \chi(k) = o(n)$ for $n > q$ for instance, ...
Amomentum's user avatar
  • 385
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1 answer
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Lets say we are having 4 "N" bit values, and in each of them there is exactly 1 10-bit pattern of "1000000001" somewhere (x can be 0 or 1, and it will be exactly N-10) - ...
Dave's user avatar
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Let $(a_n)_{n \in \mathbb{N}}$ be a sequence of complex numbers. Furthermore, suppose that exists some $z_0 \in \mathbb{C}$ such that $\sum_{n=1}^{\infty}\frac{a_n}{n^{z_0}}$ converges. Now, my goal ...
J P's user avatar
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3 votes
1 answer
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I'd like to find a closed-form formula for $$\sum_{k=1}^{n-2} [(-k + (-1)^k)^2 - 3]$$ using the indefinite summation method. That would be fine besides this annoying factor $(-1)^k$ for the expanded ...
Robert Barg's user avatar
1 vote
1 answer
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Let f be an arithmetic function and let $F(s)$ be its Dirichlet series $\sum_{n=1}^{\infty}f(n)n^{-s}$. We say f has an analytic mean value A if $F(s)=\frac{A}{s-1}+o(\frac{1}{s-1})$ as $s\rightarrow ...
Aaron Andersen's user avatar
1 vote
0 answers
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It is easy to prove that for $0<q<1$, $\sum_{k=0}^{n} q^{(2k+1)^{3/2}}$ converges because it is always increasing and it is always smaller than the convergent series $\sum_{k=0}^{n} q^{2k+1}$ ...
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2 votes
1 answer
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Let $(X_n)_{n \in \mathbb{N}}$ be a sequence of indepent random variables all uniformly distributed on $[-1,1]$ Calculate the probability that $$\sum_{n=1}^{\infty}{\frac{X_n}{n}}$$ converges Using ...
Paul's user avatar
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2 votes
2 answers
164 views

This is something I stumbled upon a few years back, and has a geometrically intuitive explanation, as well as being useful in summing powers of integers. However, with some occasional attempts at an ...
Corlin Fardal's user avatar
1 vote
0 answers
37 views

Given function of $\tau(n,\vartheta)$ denotes $\sum_{d|n}d^{i\vartheta}$ for $\vartheta\neq 0$. Also, here $e(x)=\exp(2\pi ix)$. The book mentioned the theorem to be used for the exercise (problem ...
W. Wongcharoenbhorn's user avatar
2 votes
1 answer
261 views

Given a sequence $\left(a_n \right)$, the operators $\Delta, E$ are defined by $$\Delta a_n=a_{n+1}-a_n,\\Ea_n=a_{n+1}.$$ Let $\left(u_n \right)$ and $\left(v_n \right)$ be two sequences. Let $\...
The Substitute's user avatar
1 vote
1 answer
118 views

Suppose that $\lambda_1(A) \geq \lambda_2(A) \geq \cdots \geq \lambda_n(A)$ are (real) eigenvalues of a Hermitian matrix $A$ and denote the empirical measure by $L_A:= \frac{1}{n}\sum_{i=1}^n \delta_{\...
Fei Cao's user avatar
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