518 reputation
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bio website imsc.res.in/~amri
location Chennai, India
age 39
visits member for 3 years, 8 months
seen yesterday

Professional mathematician.


1d
awarded  Constituent
Dec
16
awarded  Caucus
Nov
11
comment show that Mn(R) is not commutative
@Amudhan $AB = BA$ can be thought of as polynomial equations in the entries of $A$ and $B$. The set of solutions of such equations is of lower dimension.
Nov
11
comment “Number of zeroes of $f \leq \deg f$” used in a proof.
Gern geschehen!
Nov
11
comment “Number of zeroes of $f \leq \deg f$” used in a proof.
Non-zero polynomials certainly are.
Nov
11
comment show that Mn(R) is not commutative
Write down two random matrices. Chances are that they will not commute.
Nov
11
answered “Number of zeroes of $f \leq \deg f$” used in a proof.
Nov
9
comment If $A,B$ are commuting diagonalizable complex matrices , then $A,B$ have a common eigen-basis ?
First prove the following: If $AB = BA$, then each eigenspace of $A$ is preserved by $B$.
Apr
16
comment Construct matrix of ones and zeros based on sequences
yes, your comment to the question is not off the mark - indeed such a matrix need not always exist. On the other hand, the Gale-Ryser theorem gives a necessary and sufficient condition for its existence for general sequences.
Apr
16
comment Construct matrix of ones and zeros based on sequences
If they don't sum up to the same constant, then the answer is somewhat trivially no, because the sums of both sequences will be the total number of $1$'s in the matrix.
Apr
16
comment Construct matrix of ones and zeros based on sequences
Then I am missing something.
Apr
16
awarded  Organizer
Apr
16
revised Construct matrix of ones and zeros based on sequences
Added a couple of tags
Apr
16
suggested approved edit on Construct matrix of ones and zeros based on sequences
Apr
16
answered Construct matrix of ones and zeros based on sequences
Mar
15
comment If $AB=BA$ then they are diagonal
This is clearly false, take $A$ arbitrary and $B=A$. There is however, a statement that if $A$ and $B$ are diagonalizable and $AB=BA$ then $A$ and $B$ are simultaneously diagonalizable.
Feb
20
comment Suppose H and K are subgroups of a group G. If |H| = 12 and |K| = 35, what is |H intersection K|?
What can the cardinality of $H\cap K$ be?
Feb
18
awarded  Critic
Feb
17
comment Why is $\text{Hom}(V,W)$ the same thing as $V^* \otimes W$?
Have you thought about why it is $V^*\otimes W$ and not $V\otimes W$?
Feb
14
comment Calculating centre of rotation given point coordinates at different positions
It's called "Problems and Solutions" in the Mathematics Newsletter of the Ramanujan Mathematical Society. If you send me e-mail address (mine can be found at imsc.res.in/~amri, I can get in touch with you).