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truebaran
  • Member for 8 years, 4 months
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  • Poland
25 votes
Accepted

Is every injective function invertible?

8 votes

Series in a space which is not complete

7 votes

Help me understand infinity

5 votes

What exactly is real number?

5 votes
Accepted

Evaluating $\lim_{n\to\infty}{n\left(\ln(n+2)-\ln n\right)}$

4 votes
Accepted

Does for $T \in B(X)$ with $\|T\|>1$ exist $T^{-1}$?

4 votes
Accepted

Proving $10\cdot n=0$ for all $n\in\mathbb{Z}$ with $n\geq 0$ using strong induction

3 votes
Accepted

What does $\sigma$ mean in this context?

3 votes

Finding roots of the polynomial $x^4+x^3+x^2+x+1$

3 votes

For $ A \in M_{m \times n}(\mathbb{R})$, does $\ker(A)$ relate to $\ker(A^T) $?

3 votes
Accepted

Reconciling different definitions of orthogonality

3 votes
Accepted

Measure of union of uncountable set

3 votes

Unbounded Linear operator in a closed domain

2 votes
Accepted

Prove if $f\colon X\to \mathbb R$, $X ⊂ \mathbb R$ is continuous, then $g(x) :=|f(x)|$, $g\colon X\to\mathbb R$ is also continuous

2 votes

what is the difference between well ordered set and totally ordered set?

2 votes
Accepted

Let $f : \mathbb{N} → \mathcal{P}(\mathbb{N})$ be given by $f(n) = \{n+1 , n+2 , n+3 , . . . \}$

2 votes

Do Riemann and Lebesgue integrals always agree?

2 votes

Definition of a compact operator

2 votes

Why does being holomorphic imply so much about a function?

1 vote

Will the problem right?

1 vote

What does $\langle X\rangle$ mean?

1 vote

Why is the metric on $\mathbb{N}$ defined as the following?

1 vote
Accepted

Does $\delta$ have to be less then $\epsilon$ for uniform continuity?

1 vote

Why can't a open interval in $\mathbb{R}$ be compact?

0 votes

Verify matrix identity