Skip to main content
abcdmath's user avatar
abcdmath's user avatar
abcdmath's user avatar
abcdmath
  • Member for 6 years, 10 months
  • Last seen this week
6 votes
2 answers
538 views

Is the map sends $T$ to $T^*$ adjoint of $T$ surjective?

5 votes
3 answers
358 views

spectrum of an element of unital banach algebra is closed set

5 votes
2 answers
387 views

Integrate $\int_{0}^{\pi} \frac{1}{1+3^{\cos x}} dx.$

5 votes
0 answers
125 views

Existence of a postive measurable set such that $T^{-k}(E)\cap E=\emptyset$ for a particular $k\ge 1.$

4 votes
2 answers
130 views

Uniformly continuity of a real valued function $f$

4 votes
2 answers
677 views

Ideal of a Polynomial ring $R$ which is not principal.

4 votes
1 answer
286 views

$S^{-1}R=0$ iff $0$ belongs to $S$.

4 votes
3 answers
728 views

Show that the operator has a chain of invariant subspaces.

4 votes
2 answers
3k views

How to say that any group of order $pqr$ is cyclic with a provided relation between $p$, $q$, $r$, where they are all distinct primes.

4 votes
4 answers
2k views

If $A=\int_{0}^{1} x^n(1-x)^ndx$ then $A^{-1} \in \mathbb{N}$.

3 votes
1 answer
52 views

Bijection from $\mathbb{N}$ to $\mathbb{N}$ such that $f(n) \geq n \text{ for large } n$ or $f(n) \leq n \text{ for large } n$ holds.

3 votes
0 answers
143 views

Find all possible primes $p$ and $q$ such that $3p^{q-1}+1$ divides $11^p+17^p$.

3 votes
1 answer
2k views

The automorphisms of the extension $\mathbb{Q}(\sqrt[4]{2})/\mathbb{Q}$.

3 votes
2 answers
3k views

Isomorphism between quotient space $X/M$ and the orthogonal complement of $M$.

3 votes
1 answer
236 views

Find the average value of $i_1i_2+i_2i_3+........+i_9i_{10}+i_{10}i_1$

3 votes
1 answer
525 views

Equal integration of continuous functions gives equality of measures [duplicate]

2 votes
1 answer
85 views

The element $z \in M$ commutes with every element of $M$

2 votes
1 answer
46 views

Confused on some parts in the proof of $p \in A'' \implies (A')_p=(A_p)'$

2 votes
1 answer
50 views

A question about a projection in a W$^*$-algebra

2 votes
1 answer
113 views

The center of a von Neumann algebra may or may not have minimal projections

2 votes
2 answers
96 views

solve for $x$, $(\sqrt{a+ \sqrt{a^2-1}})^x+(\sqrt{a- \sqrt{a^2-1}})^x=2a$

2 votes
2 answers
199 views

$ABCD$ is a quadrilateral with $AB=BC$ and $BC||DA$ and $\angle ABD = x$, $\angle CBD=3x$, $\angle ADC=8x$. Then find the value of $x$.

2 votes
3 answers
2k views

Find locus of $\Delta ABC$ centroid with orthocentre at origin and side slopes 2, 3 and 5

2 votes
1 answer
150 views

Eliminate $\theta$ from the equation $\sec \theta + \tan \theta = a+\sqrt b,$

2 votes
3 answers
75 views

If $x|y^2 ~~\text{ and } ~~ y|z^2$ then prove or disprove: $x$ divides $z^2$.

2 votes
1 answer
267 views

find the possible pairs of $~(x,y)~$ such that $~x,y~$ are natural numbers and $x^2=1+4y.$

2 votes
1 answer
56 views

The sequence $\left\{n^2f\left(\frac{1}n\right)\right\}$ is bounded where $f:\mathbb C \to \mathbb C$ is analytic

2 votes
2 answers
100 views

Prove that the series $\sum_{n=1}^{\infty} x_n$ diverges in a Hilbert space $~X$

2 votes
1 answer
105 views

$L_q[0,1]~~$ is a closed proper subspace of $~~L_p[0,1]$

2 votes
2 answers
81 views

Probability of $13$ men and $2$ women divided in $3$ equal groups such that no women are in same group

1
2 3 4 5 6