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Rabi Kumar Chakraborty
  • Member for 4 years, 4 months
  • Last seen this week
  • Halisahar, Kanchrapara, West Bengal, India
14 votes
2 answers
541 views

On a ring $R$ such that every subring of $R$ is an ideal .

7 votes
2 answers
142 views

A problem regarding the rank of a matrix

5 votes
4 answers
117 views

A problem regarding the in-equality of complex numbers .

5 votes
0 answers
210 views

A problem on group homomorphism .

5 votes
1 answer
68 views

On isomorphism of two quotient of polynomial rings

4 votes
0 answers
97 views

Is $\sqrt {f(x)}$ infinitely differentiable? [duplicate]

4 votes
1 answer
65 views

A problem regarding the conjugacy classes of homeomorphism group .

3 votes
2 answers
135 views

Does $-1$ have a square root in the ring $\frac{\mathbb R[x]}{\langle(x^2+1)^2\rangle}$? [duplicate]

3 votes
1 answer
82 views

A problem regarding the product of all the elements of $U_n$ for some selected $n$

3 votes
4 answers
147 views

Evaluate the following limit: $\lim_{k \to \infty} \int_0^1 e^{- (k^2x^2/2)} dx$

3 votes
2 answers
111 views

Problem on the compactness of a subset of $\mathsf{M}_n(\mathbb{R})$

3 votes
1 answer
283 views

If in a group $G$ , $(ab)^2=(ba)^2$ for all $a,b \in G$ , then show that $G$ is abelian .

3 votes
2 answers
431 views

Show that the function $f(x)= \arcsin(x)$ is Lipschitz on $[-1,1]$

3 votes
1 answer
165 views

Is there any underlying relationship between an even function and a symmetric matrix , as well as an odd function and a skew symmetric matrix?

3 votes
1 answer
67 views

In a metric space $X$, the boundary of an open set is the set of all limit points of a discrete set .

3 votes
1 answer
484 views

If A is an $n\times n$ square matrix such that $A^3=A$ , then show that $\operatorname{rank}(A) + \operatorname{tr}(A)$ is even

3 votes
0 answers
100 views

Linear isometry between $\mathcal l_p$ and $\mathcal l_q$ norms in $\mathbb R^n$ implies $p$ and $q$ are conjugate exponents

3 votes
3 answers
254 views

$X=H - \{(0,0)\}$ is contractible where $H =\{(x,y) | y\geq 0\}$

2 votes
1 answer
51 views

Problem on finding integral submanifold of a smooth rank-$2$ distribution .

2 votes
2 answers
135 views

The quotient field of an unique factorisation domain is never algebraically closed .

2 votes
0 answers
68 views

Show that if $n$ is odd, then $\frac {RP^n}{RP^{n-2}} \simeq S^n \vee S^{n-1} $

2 votes
1 answer
65 views

Computing limits in matrix exponential

2 votes
1 answer
70 views

Is Banach algebra $L^1(\mathbb T)$ under convolution a division algebra?

2 votes
0 answers
35 views

On convergence of the same sequence under two different norms.

2 votes
1 answer
44 views

A question on group representation .

2 votes
3 answers
135 views

Cardinality of the family of all possible connected subsets of $\Bbb R^n$

2 votes
0 answers
81 views

Test either the following series is convergent or not : $(\cos{1})+(\cos{2})^2+(\cos{3})^3+(\cos{4})^4+...+(\cos{n})^n+...$

2 votes
0 answers
55 views

A problem regarding polynomials with only prime powers [duplicate]

2 votes
2 answers
72 views

A problem regarding the ratios $\frac{f(x)}{g(x)}$ and $\frac{g(x)}{h(x)}$, assuming $f(x)g(y) = h\big(\sqrt{x^2+y^2}\big)$

2 votes
2 answers
35 views

A problem regarding the value of the derivative of a real valued function

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