bio  website  fph.altervista.org 

location  Pisa, Italy  
age  31  
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Numerical linear algebra. Mainly matrix equations and their applications (control theory, applied probability).
12h

reviewed  Approve Prehomogeneous vector spaces 
Dec 17 
revised 
ULU Decomposition of a matrix
edited tags 
Dec 14 
comment 
when can I say that $UV^T$ is a permutation matrix?
If you want to define a "distance from being a permutation matrix", the obvious candidate is $$\min_{P \in \text{Permutation matrices}} \AP\,$$ where $\\cdot\$ is a matrix norm. 
Dec 13 
comment 
Suggestions for good notation
@J.M. That "Matlab notation" actually first appeared in ALGOL and FORTRAN in the 60s. 
Dec 11 
revised 
How to generate $n$ FP32 rationals s.t. no two distinct kel. subsets have same sum?
added 314 characters in body 
Dec 11 
answered  How to generate $n$ FP32 rationals s.t. no two distinct kel. subsets have same sum? 
Dec 10 
revised 
Batch Markov Arrival Process  Computing Ps(t)
latex + tags 
Dec 7 
revised 
Compute adjugate matrix over commutative ring
added 93 characters in body 
Dec 7 
comment 
Compute adjugate matrix over commutative ring
@NicolasMalebranche You are correct about the determinant. The algorithm I suggested won't work then. I am still not convinced that there cannot be a simple trick to make those simplifications 'automatically', though. 
Dec 5 
answered  Compute adjugate matrix over commutative ring 
Dec 5 
comment 
Compute adjugate matrix over commutative ring
I think that you can run Gaussian elimination keeping the denominators written formally instead of computing them. To compute sums you just reduce everything to common denominator. In the end you'll end up with a "formal denominator" equal to the product of the pivots, that is, the determinant. You just strike it out and it's done. 
Dec 1 
revised 
perturbation of Invariant subspaces
clarified some expressions 
Dec 1 
revised 
perturbation of Invariant subspaces
added 207 characters in body 
Dec 1 
answered  perturbation of Invariant subspaces 
Dec 1 
comment 
Eigenvalues of Symmetric Tridiagonal Matrices
The one in the question is not a Toeplitz matrix. 
Nov 28 
comment 
What problem would you base your mathcoin on?
Personally, I would rather see computing power itself treated as a currency. "Hey, I have this computation to make, can you make it? It'll cost 1$ per Teraoperation." Current cryptocurrencies are the computational equivalent of a onetrick pony; there is one single operation to perform, and hardware specialization is encouraged, rather than the use of generalpurpose massively parallel computing machines. 
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. 