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Born to be proud
  • Member for 9 years
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9 votes
1 answer
344 views

A problem about abelian group

7 votes
2 answers
595 views

Are these conditions equivalent to the definition of regular coordinate ball?

7 votes
3 answers
958 views

Is a differentiable manifold Hausdorff?

4 votes
1 answer
356 views

What kind of ring $R$ makes $\mathcal O(\mathrm{Proj}\,R[x_0,\cdots,x_n])=R$?

4 votes
1 answer
302 views

Is $R$ finitely generated?

3 votes
0 answers
175 views

How to show the morphisms $f_i$ glue to a morphism $f:X\to Y$.

3 votes
1 answer
226 views

Do we have $(\mathcal L\otimes_{\mathcal O_X}\mathcal L)(X)=\mathcal L(X)\otimes_{\mathcal O_X(X)}\mathcal L(X)$?

3 votes
1 answer
204 views

How to calculate the integral?

3 votes
1 answer
51 views

How to show $h=g$ a.e. $[m]$?

3 votes
1 answer
107 views

Do we have $\mathcal O_X(1)(X)=S_1$?

3 votes
0 answers
69 views

Is the projection $p: X\times_Z Y\to Y$ also an immersion?

3 votes
0 answers
43 views

Is $U\times_SY$ dense in $X\times_SY$?

3 votes
0 answers
115 views

Is the presheaf defined by $U\mapsto (\mathcal I(U))^2$ a sheaf of ideals of $\mathcal O_X$?

3 votes
2 answers
40 views

Are the two morphisms $T^i(C)\to T^{i+1}(A)$ the same for each $i$?

3 votes
1 answer
39 views

Is the morphism $\mathcal F^\dagger \to \mathcal G^\dagger$ induced by $f$ injective?

3 votes
0 answers
74 views

How to show $M$ is a finitely generated $A$-module?

2 votes
1 answer
94 views

Is the ring $R$ a commutative ring with identity in the Freyd–Mitchell embedding theorem?

2 votes
1 answer
557 views

If $M$ is a smooth manifold with boundary, $f \in C^\infty(M)$, $b$ a regular value of $f$, then is $f^{-1}((-\infty,b])$ a regular domain in $M$?

2 votes
1 answer
541 views

How to understand the definition of cohomological functor?

2 votes
1 answer
41 views

Is $dF(T_{(p,s)}W)=T_qX$ a typographical error?

2 votes
1 answer
44 views

How to show $\theta: H\times N\to N$ defined by $\theta(h,n)=hnh^{-1}$ is smooth?

2 votes
1 answer
95 views

How to show $(dx_1)_y,\cdots,(dx_r)_y$ generate a free submodule of rank $r$ of $\mathcal O_{X,y}$-module $(\Omega_{X/k})_y$?

2 votes
1 answer
92 views

What does the scheme $H\cap X$ mean?

2 votes
1 answer
168 views

Does there exist a prime ideal $\mathfrak q\notin X$ with $\mathfrak q\subseteq\bigcup_{\mathfrak p\in X}\mathfrak p$?

2 votes
1 answer
81 views

Is $\mathcal I$ a quasi-coherent sheaf on $X$?

2 votes
1 answer
26 views

How to show the existence of $\alpha_1,\cdots,\alpha_n$ as a basis of $L|K$ which is contained in $B$?

2 votes
2 answers
7k views

What's the meaning of "twice continuously differentiable"?

2 votes
1 answer
203 views

Do we have $\mathit\Gamma_*(\mathcal O_X)\cong S$?

2 votes
2 answers
73 views

Do we have $(gf)^*\mathcal F=f^*(g^*\mathcal F)$?

2 votes
1 answer
50 views

Is $i^*(\mathcal O_{\mathrm P_S^m}(1))$ an invertible $\mathcal O_X$-module?

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