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6:18 AM
Would somebody more knowledge of this topic have a look at gersgorin-sets tag-info. For example, shouldn't it say Pupkov-Solovev instead of Pupkov-Solov?
12 hours later…
6:30 PM
Q: Proof of relationship between lax pairs and zero curvature

EsteematorI was going through a proof in some integrable systems lecture notes about the relationship between lax pairs and zero curvature. The proof starts as follows: Let $ Lf = \lambda f $, where $ L $ is a self-adjoint linear operator, $ \lambda (t)<0 $ is a simple eigenvalue, and $ f(x,t) $ is a func...

All of the above created in the same question.
A tag which might turn out to be problematic is .
Q: $AB-I$ is a projection means $BA-I$ is so?

Urgent$(AB-I) \text{ is a projection} \Rightarrow (AB-I)^2=AB-I \Rightarrow AB.AB-AB-AB+I=AB-I\\ AB^2A-3AB-3I=0\\ (BA-I)^2= BA^2B-2BA+I$ they are complex matrices. please help

Q: Project $f(x) = \sin^2(x)$ onto the plane spanned by $\sin(2x)$ and $\cos(2x)$

sfw951I approached the problem by projecting $f(x)$ onto each of the other functions (since they are an orthonormal basis) using the formula $$\langle f(x),\sin2x\rangle \sin2x + \langle f(x),\cos2x\rangle \cos2x.$$ Before I go through the computations, I wanted to make sure this is the correct approa...

This tag has been created and removed before.
Jan 21 at 14:10, by Martin Sleziak
The tag seems to be non-descriptive in the current state - it has empty tag-info, the word projection can be used in various meanings (linear algebra, equivalence relations, cartesian products). https://en.wikipedia.org/wiki/Projection_(mathematics)
Jan 21 at 14:10, by Martin Sleziak
I did no find older discussions about the . Using this SEDE query I was able to found a short-lived instance of this tag in 2012.
6:52 PM
A: Tag management 2017

Martin SleziakI suggest to remove (or even blacklist) the projection tag. The problem with this tag is that the word projection is used in many various meanings in mathematics. There is projection map in geometry and in linear algebra. In linear algebra we also have projection matrix. The term projection is ...

When looking for similar tags, I found also . The tag name is a bit more specific, but it still seems to be a problematic tag.

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