1,589 reputation
413
bio website victorliu.info
location California
age 29
visits member for 4 years, 6 months
seen 1 hour ago

Work focused on optics/physics/computational stuff. I mostly answer questions related to math, geometry, and numerics here.


Jan
27
comment How to prove that a matrix with specific property is invertible?
Ah, I misread the inequality as strictly greater than. In this case, you are right.
Jan
26
comment How to prove that a matrix with specific property is invertible?
That counterexample doesn't satisfy the stated condition. The proof is more or less given here
Jan
26
comment Sparse Matrices and Tridiagonalization.
You can easily tridiagonalize a size 1000x1000 dense matrix in almost no time on a modern computer, so there is no reason to treat such a tiny matrix as sparse.
Jan
23
revised Triple Angle Condition
Removed "incomplete" notice
Jan
23
answered Triple Angle Condition
Jan
22
comment how they deduce that $\det A=1$ just from the first coeffcient and minor
No, obviously this is only true for corresponding elements. In your equation, you must have $i=k$, and $j=l$.
Jan
22
comment how they deduce that $\det A=1$ just from the first coeffcient and minor
It should hold for any element, not just the diagonal.
Jan
22
answered how they deduce that $\det A=1$ just from the first coeffcient and minor
Jan
22
revised Lin Alg 100-Level Recursion Problem
Formatted math, unsure about exponent on first equation
Jan
22
suggested approved edit on Lin Alg 100-Level Recursion Problem
Jan
21
comment Computing N cofactors
A minor of a matrix involves removal of a row and a column, so they would be size $(N-1)\times(N-2)$. Your question doesn't make sense.
Jan
20
answered Convergence rate of the power method for finding eigenvectors
Jan
16
answered How to calculate integral involving Bessel function?
Jan
15
answered Variations of a sinc function
Jan
14
revised Volume of the intersection of two tetrahedra
Added details about volume calculation
Jan
13
answered Volume of the intersection of two tetrahedra
Jan
12
comment Is there an explicit formula for this recursive series of matrices
Why is $F$ not diagonalizable? That usually makes it easier to compute.
Jan
12
answered Is there an explicit formula for this recursive series of matrices
Jan
9
answered Finding a multiplying matrix from its resultant.
Jan
9
answered Eigenvectors of self-adjoined matrix with respect to a general inner product