# Tag Info

## Hot answers tagged notation

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Accepted

### What does this symbol mean in set theory? c/=

What you did in Photoshop is not the symbol. Schuller writes on the board $C \subseteqq \mathcal{O}$ to mean a collection of open sets. Here $\subseteqq$ should be interpreted as $\subseteq.$
• 7,595

### Notation for repeating the concatenation operation

The answer to whether "it is okay" for you to express concatenation like that is always "yes". It's okay for you to do anything as long as you explain yourself. No one is stopping ...
• 4,496
1 vote
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Assuming that you are talkink about binary relations. One notation to denote that $a$ is related to $b$ is $aRb$, and if that relation does not hold to write $\lnot aRb$ or less ambiguously $\lnot(aRb)... • 7,762 1 vote Accepted ### Is the following notation common in calculus books?$\int_{0}^{\frac{\pi}{2}} (1-\sin^2\theta)\,d(\sin\theta)$American Calculus books usually use such notation in the context of Riemann-Stieltjes integration, but not for regular Riemann one. I know the Russian analysis books use this notation very frequently. ... • 52.5k 1 vote Accepted ### What does$[\mathbf{a}]_\times\mathbf{b}$mean? The above transforms a vector function into a linear algebra matrix product$\$ \begin{pmatrix} a_x \\ a_y \\ a_z \end{pmatrix} \times \begin{pmatrix} b_x \\ b_y \\ b_z \end{pmatrix} = \begin{bmatrix} ...
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