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21:21
@CroCo A linear map A: V -> V on an inner product space is called positive definite if <Av, v> is non-negative for all v, and zero only when v = 0
Like A = 1
21:34
Anyone know about quotienting a monoid?
Can I do it for a finite set of pairs of elements?
Like pin those two elements together
doing so forms an equiv relation, but I don't think congruence
So to get multiplicativity you have to ?
do what with the pairs of elements?
must be dinner time at Harvard
:D
where have all the answerers gone
long time ago
21:51
Nope, don't know about quotienting a monoid. Might be that no one else currently here does, either.
@Rithaniel what about free groups?
I switched the question over to that format
1
Q: How to quotient the free group by a set of elements?

Shine On You Crazy DiamondLet $F =$ the free group generated by $\Sigma \cup V$ where $\Sigma = \Sigma(s)$ is the minimal alphabet that $s$ is over, and $V = \{V_1, \dots, V_n\}$ is a finite set of variables. I would like to quotient by the smallest normal subgroup containing all of $V_i^{-1} v_i$ where $v_i = $ a substr...

The free group might be easier to quotient with
22:04
Well, if you can quotient it, then you must be quotienting by a normal subgroup, correct? Or are you wanting to quotient by any arbitrary subset?
If the former, you just look at your normal subgroup and say that $a\sim b$ if $ab^{-1}$ is in that subgroup
If the latter, I believe you might have well-definedness issues if you want to somehow develop a partition on the free group using group properties.
Does anyone have a good mathematical notation list the one on Wikipedia is a little scattered and some of them are not well defined
Like a Comprehensive mathematical and scientific notation list with all the Greek and latex symbols im trying to put one together in excel. Who here is into robotics I’m trying to make some robot minions one day
22:25
@Rithaniel a person answered
22:46
I have a question
In this MO post below:
62
A: Atiyah-MacDonald, exercise 2.11

Balazs StrennerHere is another solution using only the Cayley-Hamilton Theorem for finitely generated modules (Proposition 2.4. in Atiyah-Macdonald) which, even though looks quite innocent, is a very powerful statement. Assume by contradiction that there is an injective map $\phi: A^m \to A^n$ with $m>n$. The ...

For answer using Cayley-Hamilton
Why should the characteristic polynomial of minimal degree have constant term not 0?
The endomorphism ring is not necessarily without zero-divisors
For example just take the simple Z/nZ example
Let n be a compositive with nontrivial factorization n=ab
Then f(x)=ax composites with g(y)=by is zero while non of f or g is itself 0.
Correction: “Let n be a composite with...”
Oh does it follow from the injectivity?
23:02
0
Q: Different values for an integral and a sum due to the difference in measure?

UltradarkFrom a measure theory perspective how do I understand, notate, and evaluate the following, where $\pi(x)$ is the prime counting function. I think I need to choose a measure $\mu$ on a set $X.$ Also, what is the correct notation for the sum and integral below? $$ \sum_{1/100}^1 \pi(1/x)=~?$$ $$...

23:32
Hey guys, how would you go about proving $(x+y+z+w) / 4$ ≥ $\sqrt[4]{xyzw}$ for all $x, y, z, w ≥ 0$ using AGM?
I'm a little lost, and not exactly sure how to start.
I know that you can use the THM 3 times ($\frac{x+y}{2}≥\sqrt{xy}$), but I don't know how to apply it.
@Abwatts that's exactly what AGM says
or maybe your AGM is only for 2 variables
note that the left hand side is AM(AM(x,y),AM(z,w))
what can you say about the right hand side?
23:49
That the right-hand side will always be smaller than the left side?
So for the left side, are you supposed to let 2 variables represent the AM (for instance, a and b), and then simply simplify the expression as much as you can to arrive at something that's true?
The numbers 1 through 10 in sign languages around the world
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