11,198 reputation
13973
bio website TheBigQuestions.com/blog
location
age
visits member for 3 years, 5 months
seen 7 mins ago

Apr
13
comment computing integral of dz/(z+1) on unit circle
Please do not answer off topic questions.
Apr
12
awarded  Civic Duty
Apr
9
comment coin reversal puzzle with one hand and two stacks
It would be really good to reword this so that it does not appear at first glance like the answer might depend on your manual dexterity.
Apr
2
comment Non-cohomological proof that a noetherian scheme $X$ is affine if its reduction $X_{red}$ is affine
The argument given in the comment to the linked question seems to answer this. The only cohomology group invoked is an $H^1$ that could easily be defined without reference to derived functors.
Apr
1
revised Quillen's motivation of higher algebraic K-theory
added 1 characters in body
Mar
31
answered Quillen's motivation of higher algebraic K-theory
Mar
29
comment Find sufficient and necessary conditions on $f$ in which the level curve $f(x,y)=0$ implies only one case $x=a$ for all real $y$
Does this mean that there exists an $a$ such that for all $y$, $f(x,y)=0$ implies $x=a$? Or does it mean that for all $y$, there exists an $a$ such that $f(x,y)=0$ implies $x=a$?
Mar
27
revised What geometric information is carried by the Fourier coefficients of the components of a closed curve?
changed "smooth curve" to "smooth closed curve" in first sentence.
Mar
17
awarded  Notable Question
Mar
14
awarded  Nice Answer
Mar
14
awarded  Nice Answer
Mar
12
revised Source for Derogatory Quote About Graph Theory
edited body; edited title
Mar
12
comment Origin of exact sequences
This abstract not only answers the OP's first question; it's also a great answer for the second.
Mar
12
comment Origin of exact sequences
@Spock: Neither could I. But it's in Hurewicz's collected works.
Mar
12
answered Origin of exact sequences
Mar
10
comment Sources in unimodular rows
You could start with Bass's book on Algebraic K-theory. You can also work through the many papers of people like Vaserstein and Suslin that make heavy use of unimodular rows. There's a paper by Swan and Towber called "A Class of Projective Modules That Are Nearly Free" that has some nice simple applications of these ideas, and would surely help to give you the flavor of the subject.
Mar
10
awarded  Nice Answer
Mar
7
comment intersection of finitely many maximal ideals
Equally obviously, you can drop the word "Dedekind"....
Mar
6
accepted Mean of i.i.d Random Variables With No Expected Value
Mar
6
answered Does the going-up theorem hold between flat algebras?