bio | website | fph.altervista.org |
---|---|---|
location | Pisa, Italy | |
age | 31 | |
visits | member for | 5 years |
seen | 6 hours ago | |
stats | profile views | 2,178 |
Numerical linear algebra. Mainly matrix equations and their applications (control theory, applied probability).
Nov 18 |
awarded | Yearling |
Nov 16 |
comment |
Open source mathematical software.
Is the list of capabilities missing, or is it the empty set? :) |
Nov 16 |
comment |
Open source mathematical software.
@kundor Actually the Geogebra page on licensing now seems clearer than when I wrote my previous comment. The program itself is GPL, and the additional restrictions are on additional components such as the web plugin, the installer and the translations of the interface in other languages. I still disagree with the claim "GeoGebra is open source software", but at least everything is consistent. |
Nov 16 |
comment |
Open source mathematical software.
@kundor Sure, but you cannot forbid those who already have the software from redistributing it (even to commercial users), which usually makes selling it quite pointless. The commercial use clause falls under the "further restrictions" cause and is invalid in my view. And the contradiction (1)-(2) stands clear in the OSI definition, if one assumes that as the definition of open source. |
Nov 15 |
comment |
Obscure Names in Mathematics
Similar to the Killing-Hopf theorem, the Italian name for the Gaussian elimination method sounds like someone is debating on the best way to kill poor C.F. Gauss. |
Nov 14 |
comment |
Modified Orthonormal Procrustes Problem
You're right, sorry, my bad. :/ |
Nov 14 |
comment |
Modified Orthonormal Procrustes Problem
If $C$ is square and orthogonal, $||Y-XC||_F=||(Y-XC)C^T||_F=||YC^T-X||_F$, since the Frobenius norm is invariant by orthogonal transformation. Am I missing something? |
Nov 11 |
comment |
iterative solution better than analytic solution?
There are exact formulas that are less accurate than an iterative algorithm. There should be examples for problems as simple as solving a quadratic, if you take a case when the "textbook" exact formula uses dangerous subtractions. |
Nov 10 |
revised |
About Sylvester's determinant
two versions of Schur cpl |
Nov 10 |
revised |
About Sylvester's determinant
added reference to Schur complements. |
Nov 10 |
answered | About Sylvester's determinant |
Nov 4 |
comment |
minimal polynomial for a graph
Your statement on Krylov subspaces seems false; counterexample: take $v$ equal to an eigenvector of $Q$. The claim holds if you reverse the order of quantifiers (the least $m$ such that for each $v$ $K_m(A,v)$ is $Q$-invariant is $d$). |
Nov 3 |
comment |
Partial inverse of a matrix - or does it have its own name?
@PiotrMigdal Another one of its many names is exchange operator. Maybe you find that more enlightening? |
Nov 3 |
comment |
Partial inverse of a matrix - or does it have its own name?
@PiotrMigdal Yes, it's one of those operations that pop up unexpectedly in lots of different fields. It is interesting to find out that it has an application in optics, too! |
Nov 2 |
reviewed | Approve suggested edit on moduli-spaces tag wiki excerpt |
Nov 2 |
answered | Partial inverse of a matrix - or does it have its own name? |
Nov 2 |
comment |
When exactly and why matrix multiplication became a part of undergraduate curriculum?
The formula reported in your picture is not $C=AB$ but $C=A^TB$, and the Italian text translates to "The product of two determinants of the same order can be expressed as a single determinant as follows.". So someone with more free time than I have could argue that this is not a matrix product, but simply a composition rule for determinants that happens to be related to it. |
Nov 2 |
revised |
math-education-history wiki excerpt
added 33 characters in body |
Nov 2 |
wiki | created math-education-history excerpt |
Nov 2 |
suggested | suggested edit on math-education-history tag wiki excerpt |