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seen Nov 22 at 5:49

Nov
5
awarded  Yearling
Aug
25
comment A question on resolution of singularities
Is it true that $\pi$ restricts to an isomorphism on $Y\setminus \pi^{-1}(\{p\} \cup L)$, so that it does not change any point on $\mathbb{P}^4 \setminus (\{p\} \cup L)$? If this is true then the answer is clearly negative.
Jul
2
awarded  Curious
Jun
29
revised What is the probability that a random sequence of polynomials is regular?
deleted 5 characters in body
Jun
26
answered What is the probability that a random sequence of polynomials is regular?
Mar
25
comment Jacobian of an injective mapping
@user126154: you are right. I saw in the question $J_f(a) < 0$, and immediately interpreted $J_f$ as the Jacobian determinant.
Mar
25
comment Jacobian of an injective mapping
@user126154: I meant the function $\phi: \mathbb{R} \to \mathbb{R}$ defined by $\phi(t) := J_f(a + t(b-a))$.
Mar
25
comment Jacobian of an injective mapping
For the 2nd question apply the intermediate value theorem to $J_f$-restricted to the line joining a and b.
Mar
12
accepted Why the name “variety” and the notation “V” for zeroes of polynomials?
Mar
11
awarded  Nice Question
Mar
11
asked Why the name “variety” and the notation “V” for zeroes of polynomials?
Mar
10
comment Normal polytopes - counterexample?
Regarding the 'related question': M = dim(P) -1 suffices (Theorem 2.2.12, Toric Varieties, Cox-Little-Schenck).
Feb
19
comment What are some mathematical sculptures?
@ToddTrimble: Hi Todd, it had a "coppery" look, but not sure if it was mixed with anything else.
Feb
4
accepted How many of the true sentences are provable?
Feb
1
awarded  Enlightened
Feb
1
awarded  Nice Answer
Jan
31
comment Is the induced ring homomorphism surjective for a finite injective morphism between affine varieties?
Just wanted to add that in your first statement above, "affine" is not necessary. Essentially the same argument shows that "a finite bijective morphism f:X→Y between varieties where Y is normal must be an isomorphism."
Jan
31
revised Is the induced ring homomorphism surjective for a finite injective morphism between affine varieties?
added 428 characters in body
Jan
31
answered Is the induced ring homomorphism surjective for a finite injective morphism between affine varieties?
Nov
28
comment Computing fundamental groups of the complement of plane curves
@Jason: I see I was being dense. Thanks again.