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Poseidaan
  • Member for 4 years, 8 months
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4 votes
2 answers
110 views

Why is $\int x^2e^{x^2}\,d(x^2)$ not proper notation?

3 votes
2 answers
92 views

Is this a good way to differentiate between evaluation of a function at a specific point and multiplication.

2 votes
2 answers
41 views

Is it a general truth that when two equations can be described with the same sentence, only varying intonation they are equivalent?

2 votes
1 answer
4k views

How can all matrices have a _unique_ reduced row echelon form?

2 votes
0 answers
63 views

What is the pullback of the adjoint representation on a Lie algebra?

2 votes
0 answers
75 views

Can $x$ be written as a power series in $e^x$?

1 vote
1 answer
95 views

If we want to use proof by contradiction, shouldn't we first proof that a statement is either true or false?

1 vote
1 answer
74 views

Why do we assume the set of all sets that do not contain themselves exists?

1 vote
2 answers
57 views

Why does $\cot(2\arctan(Ax))=\frac{1-(Ax)^2}{2Ax}$

1 vote
1 answer
35 views

How do I notate "the x-coördinate of $G^{-1}(z)$ for $z = G(x, y) : \mathbb{N}\times\mathbb{N} \to \mathbb{N}$

1 vote
0 answers
78 views

Why is my proof that $(A^m)^{-1} = (A^{-1})^m $ not rigorous?

1 vote
1 answer
90 views

How do we denote a surface embedded in four dimensions?

1 vote
0 answers
73 views

Why does the Hodge-star of d$x$ equal d$y$ and not -d$y$?

0 votes
0 answers
155 views

What does $\bigoplus\limits_{\mathbb N} \mathbb Z$ mean?

0 votes
0 answers
61 views

Why does $\sum_{i=1}^{n-1} {n-1 \choose i} {m+1 \choose i+1} = \frac{(m+n)!}{m!n!}$

0 votes
0 answers
46 views

If $i^2=-1$ and $j^2=1, j \neq 1$ does there any literature for $k^2=0, k\neq0$ or even $k^2 = a, a \in \mathbb{R}, k \neq \sqrt{a}$?

0 votes
1 answer
367 views

Does there exist a function $f(x)$ such that $f'(x)$ exists for all $x \in A$ but $f'(x)$ is not continuous on $A$? [duplicate]

0 votes
3 answers
97 views

Why does $\sum_{k=0}^{n} (-1)^k {n \choose k} = 0$ if $n\neq 0$ and 1 otherwise? [duplicate]

0 votes
2 answers
42 views

How to properly write down $\frac{\partial}{\partial xy } f(xy, x^2+3y-2)$

0 votes
1 answer
182 views

Volume integral of the gradient of a scalar field.

0 votes
0 answers
42 views

What is the $H^{-1}$ metric?

0 votes
1 answer
97 views

What does the metric $\dot{H}^{1/2}$ refer to?

0 votes
0 answers
21 views

Does $\langle e^{-i\tau \psi}\varphi, u\rangle = \langle\mathcal{F}^{-1}(e^{-i\tau\psi}), \mathcal{F}(\varphi u)\rangle$?

-2 votes
1 answer
45 views

Does $\int_{-\infty}^{+\infty} \frac{\partial}{\partial y}δ(x-y)\text{d}y = \frac{\partial}{\partial x}$?