Skip to main content
user102248's user avatar
user102248's user avatar
user102248's user avatar
user102248
  • Member for 10 years, 1 month
  • Last seen more than 3 years ago
9 votes
0 answers
194 views

When the element-wise product of two ideals produces an ideal

7 votes
2 answers
1k views

To compute $\tan1-\tan3+\tan5-\cdots+\tan89$, $\tan1+\tan3+\tan5+\cdots+\tan89$

7 votes
3 answers
694 views

Does the Grothendieck group of finitely generated modules form a commutative ring where the multiplication structure is induced from tensor product?

7 votes
1 answer
437 views

Group which can be written as a union of proper normal subgroups

5 votes
3 answers
310 views

Inequality $\frac 1{\sqrt{1+xy}}+\frac 1{\sqrt{1+yz}}+\frac 1{\sqrt{1+zx}}\ge \frac 9{\sqrt {10}}$

4 votes
1 answer
116 views

$f:R \to D$ a homomorphism of the additive group of rings , $f(aba)=f(a)f(b)f(a) , f(1_R)=1_D$ , then is $f$ a ring homomorphism?

4 votes
1 answer
257 views

Is any connected dimension $0$ scheme affine?

4 votes
2 answers
289 views

Can the zero set of an irreducible polynomial contain a non-empty Zariski open subset?

4 votes
2 answers
307 views

Does every closed subset of the underlying space of a Noetherian scheme admits a natural closed subscheme structure?

4 votes
1 answer
193 views

Inducing one point closed subset with a closed subscheme structure so that the stalk of the subscheme is a field

4 votes
0 answers
142 views

Grothendieck type vanishing result for Local Cohomology over not necessarily affine schemes?

3 votes
1 answer
183 views

Isomorphic as affine schemes v.s. isomorphic as affine $k$-schemes

3 votes
1 answer
83 views

On finding a finite set of generators for a certain semigroup

3 votes
1 answer
282 views

Can finitely generated reflexive module have strictly larger depth than the depth of the ring?

3 votes
1 answer
318 views

Irreducible variety over an algebraically closed field which admits only constant regular functions

3 votes
0 answers
75 views

Connected scheme of dimension $0$ which admits a monomorphism to an affine scheme

3 votes
0 answers
81 views

cancellation ideals in Noetherian domain

2 votes
1 answer
218 views

Looking for example of a surjective homomorphism on $(\mathbb R,+)$ which is not an automorphism

2 votes
1 answer
158 views

On the natural isomorphism between $I$-torsion functor and direct limit of $\mathrm{Hom}$ functor

2 votes
3 answers
300 views

Right derived functors of the $I$-torsion functor and $\varinjlim \mathrm{Ext}^i_R(R/I^n,-)$ are naturally isomorphic?

2 votes
1 answer
284 views

When does the Borel subgroups of affine (linear) algebraic groups come from Borel subgroups of general linear group?

2 votes
2 answers
817 views

If $f: D(0,1)\to \mathbb C$ is holomorphic, then there is a sequence $\{z_n\}$ in $D(0,1)$ such that $|z_n| \to 1$ and $\{f(z_n)\}$ is bounded [duplicate]

2 votes
0 answers
92 views

Given a split exact sequence $0 \to N \to M \to M \to 0$, when can we say $N=0$?

2 votes
1 answer
85 views

On the space of polynomials in $T$ (a linear operator) with no non-zero invariant subspace

2 votes
1 answer
162 views

On the subfield of $\mathbb C(x)$ fixed by the inversion of the variable

2 votes
1 answer
159 views

On the $k$-vector space dimension of graded pieces of an Artinian $k$-algebra $k[x,y]/J$

2 votes
1 answer
200 views

Canonical scheme structure on the singular locus of (affine) schemes so that the inclusion map is closed immersion

2 votes
1 answer
570 views

Prime ideals and maximal ideals of the Pullback of rings

2 votes
2 answers
107 views

Grothendieck group of Abelian categories , with "coefficients" in a ring

2 votes
1 answer
91 views

When the contravariant Hom functor of two finite type integral $k$-schemes are isomorphic on points