User my2cents

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0 answers

36 views

Why isn't natural density countably additive on the algebra generated by periodic sets?

asked Sep 20 at 6:30

-1 votes

0 answers

31 views

Extending proof that $\sigma$-algebras cannot be countable to proof that $\sigma$-algebras are finite or have cardinality $\ge |2^{\mathbb{N}}|$

asked Sep 20 at 5:38

0 votes

0 answers

51 views

Exercise 4.30 of Eisenbud: how to connect a maximal ideal in a localization with the original ring's property of being finitely generated?

asked Mar 11 at 23:10

2 votes

1 answer

215 views

What's so special about the number 24 in the definition of the Ramanujan tau function?

asked Dec 3, 2022 at 23:03

8 votes

1 answer

641 views

Geometric intuition for adjoint

asked Dec 14, 2021 at 19:06

2 votes

1 answer

83 views

Are unitarily and orthogonally diagonalizable equivalent over the complex numbers $\mathbb{C}$?

asked Dec 14, 2021 at 1:44

1 vote

0 answers

136 views

How to prove that the vector space of all $n \times n$ matrices is the direct sum of the vector spaces of symmetric and skew-symmetric matrices?

asked Aug 31, 2021 at 22:30

4 votes

2 answers

115 views

Is there any way to refer to a function $f$, without defining $f$? [closed]

asked Aug 12, 2021 at 19:56

0 votes

1 answer

311 views

How to prove that if $T$ is diagonalizable and $T^3=T^2$, $T^2=T$? [duplicate]

asked Aug 13, 2021 at 18:55

1 vote

2 answers

316 views

Help proving $T$ and $S^{-1}TS$ have the same eigenvalues

asked Aug 8, 2021 at 5:58

0 votes

0 answers

40 views

How to prove or disprove that all linear maps from $\mathbb{R}^3$ to $\mathbb{R}^3$ have a real eigenvalue? [duplicate]

asked Aug 8, 2021 at 18:41

2 votes

0 answers

109 views

Can we combine set notation and interval notation?

asked Sep 6, 2020 at 0:34

2 votes

1 answer

138 views

Can we define $\ln(x)$ as a solution of $\frac{d}{dx}(f(x))=\frac{1}{x}$?

asked Sep 4, 2020 at 19:21

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13 Questions

Why isn't natural density countably additive on the algebra generated by periodic sets?

Extending proof that $\sigma$-algebras cannot be countable to proof that $\sigma$-algebras are finite or have cardinality $\ge |2^{\mathbb{N}}|$

Exercise 4.30 of Eisenbud: how to connect a maximal ideal in a localization with the original ring's property of being finitely generated?

What's so special about the number 24 in the definition of the Ramanujan tau function?

Geometric intuition for adjoint

Are unitarily and orthogonally diagonalizable equivalent over the complex numbers $\mathbb{C}$?

How to prove that the vector space of all $n \times n$ matrices is the direct sum of the vector spaces of symmetric and skew-symmetric matrices?

Is there any way to refer to a function $f$, without defining $f$? [closed]

How to prove that if $T$ is diagonalizable and $T^3=T^2$, $T^2=T$? [duplicate]

Help proving $T$ and $S^{-1}TS$ have the same eigenvalues

How to prove or disprove that all linear maps from $\mathbb{R}^3$ to $\mathbb{R}^3$ have a real eigenvalue? [duplicate]

Can we combine set notation and interval notation?

Can we define $\ln(x)$ as a solution of $\frac{d}{dx}(f(x))=\frac{1}{x}$?