Stack Exchange

Makoto Kato

top accounts reputation activity favorites subscriptions
Top Questions
85 votes

Classification of prime ideals of $\mathbb{Z}[X]$

abstract-algebra commutative-algebra ideals prime-ideals asked Jul 24 '12 at 9:38
math.stackexchange.com

66 votes

Is memory unimportant in doing mathematics?

soft-question learning asked Nov 17 '12 at 1:44
math.stackexchange.com

44 votes

Are the exercises necessary to understand the subject of a mathematical textbook?

soft-question learning asked Jun 28 '12 at 2:29
math.stackexchange.com

43 votes

Is an automorphism of the field of real numbers the identity map?

abstract-algebra field-theory real-numbers asked Jul 22 '13 at 12:00
math.stackexchange.com

33 votes

Unramification of a prime ideal in an order of a finite Galois extension of an algebraic number field

algebraic-number-theory asked Aug 17 '12 at 6:22
math.stackexchange.com

33 votes

Do native speakers distinguish well the pronunciations of “L” and “R”?

pronunciation phonology asked Oct 12 '15 at 0:50
ell.stackexchange.com

27 votes

Mnemonic for the fact that a right(left) adjoint functor preserves limits(colimits)

category-theory adjoint-functors asked Jan 5 '13 at 15:55
math.stackexchange.com

26 votes

“No more Hiroshima” or “No more Hiroshimas”

grammatical-number proper-nouns negative asked Jan 14 '15 at 10:52
ell.stackexchange.com

23 votes

A natural proof of the Cauchy-Schwarz inequality

functional-analysis inequality asked Jul 5 '13 at 5:31
math.stackexchange.com

21 votes

Why did a famous mathematician say that algebraic topology was dead?

algebraic-topology soft-question asked Sep 13 '12 at 0:05
math.stackexchange.com

1 2 3 4 5 … 10

Top Answers
52
Is an automorphism of the field of real numbers the identity map?
math.stackexchange.com

48
Abelian categories and axiom (AB5)
math.stackexchange.com

42
Is there a purely algebraic proof of the Fundamental Theorem of Algebra?
math.stackexchange.com

27
Constructing a Galois extension field with Galois group $S_n$
math.stackexchange.com

26
Verifying that the ideal $(x^3-y^2)$ is prime
math.stackexchange.com

20
nontrivial theorems with trivial proofs
mathoverflow.net

20
Prove that $\mathbb{R^*}$, the set of all real numbers except $0$, is not a cyclic group
math.stackexchange.com

18
Spivak's proof of Inverse Function Theorem
math.stackexchange.com

17
Why a polynomial is solvable by radicals iff its Galois group is solvable, when $char(F)=0$?
math.stackexchange.com

17
Showing a homomorphism of a field algebraic over $\mathbb{Q}$ to itself is an isomorphism.
math.stackexchange.com

16
How can I prove formally that the projective plane is a Hausdorff space?
math.stackexchange.com

15
Find all subgroups of $\mathbb{Z}\times\mathbb{Z}$.
math.stackexchange.com

14
If $K$ is an extension field of $\mathbb{Q}$ such that $[K:\mathbb{Q}]=2$, prove that $K=\mathbb{Q}(\sqrt{d})$ for some square free integer $d$
math.stackexchange.com

13
Theorems with an extraordinary exception or a small number of sporadic exceptions
math.stackexchange.com

13
Compositum of abelian Galois extensions is also?
math.stackexchange.com

13
Prove $\sin x$ is uniformly continuous on $\mathbb R$
math.stackexchange.com

12
Why are topological spaces interesting to study?
math.stackexchange.com

12
An element of a group $G$ is not conjugate to its inverse if $\lvert G\rvert$ is odd
math.stackexchange.com

12
Find the number of non-zero squares in the field $Zp$
math.stackexchange.com

12
Easy way to show that $\mathbb{Z}[\sqrt[3]{2}]$ is the ring of integers of $\mathbb{Q}[\sqrt[3]{2}]$
math.stackexchange.com

11
how to show that power series is analytic inside the radius of convergence?
math.stackexchange.com

11
Interpreting the Cayley-Hamilton theorem
math.stackexchange.com

11
Morphism of Affine Algebraic Variety
math.stackexchange.com

11
Example of nonabelian group with all proper subgroups normal
math.stackexchange.com

10
Sheafification of a presheaf through the etale space
math.stackexchange.com

10
Discriminant of number field
math.stackexchange.com

10
Showing that a Sylow subgroup of a group of order $p^{2}q$ is normal.
math.stackexchange.com

10
Does every ring with unity arise as an endomorphism ring?
math.stackexchange.com

9
Why is the tensor product important when we already have direct and semidirect products?
math.stackexchange.com

9
Why $E$ is the algebraic closure of $K$?
math.stackexchange.com

1 2 3