MHB Max Complex Matrices of Order $n$: $\lfloor n^2/4\rfloor + 1$

MountEvariste
Messages
85
Reaction score
0
Prove that the maximum number of mutually commuting linearly independent complex matrices of order $n$ is equal to $\lfloor n^2/4\rfloor + 1.$
 
Mathematics news on Phys.org
June29 said:
Prove that the maximum number of mutually commuting linearly independent complex matrices of order $n$ is equal to $\lfloor n^2/4\rfloor + 1.$
[sp]This is a classical theorem due to Schur (1905). There is a simplified proof by Jacobson (1944), and an even simpler one by Mirzakhani (Amer. Math. Monthly 105 (1998), pp.260-262). That last paper was published when Maryam Mirzakhani was only 21. She went on to become the first female mathematician to win a Fields Medal, but died last year at the tragically early age of 40.

Not wanting to criticise, but I think it is a bit ambitious to expect MHB readers to compete with mathematicians of that calibre.

[/sp]
 
Opalg said:
[sp]This is a classical theorem due to Schur (1905). There is a simplified proof by Jacobson (1944), and an even simpler one by Mirzakhani (Amer. Math. Monthly 105 (1998), pp.260-262). That last paper was published when Maryam Mirzakhani was only 21. She went on to become the first female mathematician to win a Fields Medal, but died last year at the tragically early age of 40.

Not wanting to criticise, but I think it is a bit ambitious to expect MHB readers to compete with mathematicians of that calibre.

[/sp]

[sp]I got the problem from my linear algebra textbook by Hoffman and Kunze which is used as a first/second course on linear algebra at many universities. I couldn't do the problem, so I learned the amazing proof by Mirzakhani. I just assumed there would be other elementary solutions because the book gives it as an innocuous exercise! Probably a cruel joke! (Rofl) [/sp]
 
Last edited:
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Fermat's Last Theorem has long been one of the most famous mathematical problems, and is now one of the most famous theorems. It simply states that the equation $$ a^n+b^n=c^n $$ has no solutions with positive integers if ##n>2.## It was named after Pierre de Fermat (1607-1665). The problem itself stems from the book Arithmetica by Diophantus of Alexandria. It gained popularity because Fermat noted in his copy "Cubum autem in duos cubos, aut quadratoquadratum in duos quadratoquadratos, et...
I'm interested to know whether the equation $$1 = 2 - \frac{1}{2 - \frac{1}{2 - \cdots}}$$ is true or not. It can be shown easily that if the continued fraction converges, it cannot converge to anything else than 1. It seems that if the continued fraction converges, the convergence is very slow. The apparent slowness of the convergence makes it difficult to estimate the presence of true convergence numerically. At the moment I don't know whether this converges or not.
Back
Top