Prove the centralizer of an element in group $G$ is a subgroup of …
Stack Exchange Network. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
Is the inverse of a symmetric matrix also symmetric?
All the proofs here use algebraic manipulations. But I think it may be more illuminating to think of a symmetric matrix as representing an operator consisting of a rotation, an anisotropic scaling and a rotation back.
A cyclic subgroup is normal? - Mathematics Stack Exchange
Stack Exchange Network. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
Does $\\pi$ contain all possible number combinations?
2012年10月19日 · It is not true that an infinite, non-repeating decimal must contain ‘every possible number combination’. The decimal $0.011000111100000111111\dots$ is an easy counterex
The Monty Hall problem - Mathematics Stack Exchange
I was watching the movie $21$ yesterday, and in the first 15 minutes or so the main character is in a classroom, being asked a "trick" question (in the sense that the teacher believes tha...
Factoring $x^n + y^n$ over the integers - Mathematics Stack …
Stack Exchange Network. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
Is positive the same as non-negative? - Mathematics Stack Exchange
This has lead to the gag among my friends where appending "in the French sense" turns any open condition into a closed one. $\endgroup$ – Willie Wong Commented Jan 21, 2011 at 23:44
How to prove $\\operatorname{Tr}(AB) = \\operatorname{Tr}(BA)$?
2015年1月11日 · The efficient @hjhjhj57: answer $$\text{Tr}(AB) = \text{Tr}(BA)= \sum a_{ij} b_{ji}$$ Now we can start to understand why if we do a circular permutation of the factors the expression
Understanding the difference between group representations and …
2020年9月1日 · Stack Exchange Network. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.