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833
bio website notesonmathematics.wordpress.…
location India
age 31
visits member for 3 years, 7 months
seen 12 hours ago

A simple student.


Dec
19
asked Proving Infinite Ramsey's theorem
Dec
17
comment Is there a great mathematical example for a 12-year-old?
Out of curiosity, what other non-Ramsey directions were you thinking about?
Dec
9
awarded  Caucus
Nov
20
awarded  Nice Answer
Oct
24
accepted Deriving Van der Waerden's theorem from Rado's theorem
Oct
20
revised Deriving Van der Waerden's theorem from Rado's theorem
added 4 characters in body
Oct
20
answered Deriving Van der Waerden's theorem from Rado's theorem
Oct
20
revised Deriving Van der Waerden's theorem from Rado's theorem
deleted 3 characters in body; edited tags
Oct
20
asked Deriving Van der Waerden's theorem from Rado's theorem
Sep
18
revised Chromatic Triangles on a k17 graph
chromatic triangle should be monochromatic triangle.
Sep
2
comment Automorphisms of the Petersen graph
@user170141: I found another proof and have written it here if you are interested: notesonmathematics.wordpress.com/2013/10/09/graph-automorphisms
Aug
29
comment What is the motivation for quaternions?
@metacompactness: Suppose each number was expressed as $a_0+a_1i+a_2j$. Then letting $ij=a_0+a_1i+a_2j$ and multiplying on both sides by $i$ using field axioms shows that $j$ is a complex number. So unless we drop some of the field axioms we cannot get anything beyond complex numbers.
Aug
12
accepted Comparing a vector with a directed line segment
Aug
10
comment Comparing a vector with a directed line segment
Thanks for answering, but my question is still left unanswered. I perfectly understand that $x-y$ and $y-x$ are not the same since they have opposite directions. Please read the last two sentences again.
Aug
10
asked Comparing a vector with a directed line segment
Aug
6
reviewed Approve Proof of sequential limit theorem
Jul
31
comment Intuitive explanation of even/odd permutation
Thanks for the recommendation.
Jul
31
revised Intuitive explanation of even/odd permutation
added 159 characters in body
Jul
31
comment Intuitive explanation of even/odd permutation
(contd) My question is however is asking for a more general motivation of even/odd permutation for a fresh student. For example I used rotations in $D_n$ to motivate $\mathbb{Z}_n$. Likewise I was looking for a general motivation for even/odd permutations.
Jul
31
comment Intuitive explanation of even/odd permutation
Another way to look at it is to consider $S_n$ as the collection of matrices with rows of the identity matrix permuted. Your map above simply then becomes the determinant map. The even permutations go to $1$ and the odd permutations go to $-1$.