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| bio | website | |
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| visits | member for | 6 months |
| seen | yesterday | |
| stats | profile views | 35 |
I know basics of real analysis, linear algebra and some discrete maths / graph theory.
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May 17 |
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Quick Conditional Probability Question Thanks. Isn't it however true, in this case, that $P(A\cap B)=\emptyset$, thus 2 would be correct? |
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Apr 2 |
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Two quick eigenvalues & complex numbers questions Ha! That's exactly why I wanted to ask this, I knew I'd miss something. Thanks. |
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Mar 27 |
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Characteristic polynomial of an involution Indeed, this is beautiful! Hope one day I'll be coming up with answers like this myself. |
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Mar 27 |
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Characteristic polynomial of an involution Thanks! So ${\lambda}^2=1$ thus $\lambda$ cannot have an imaginary part, is that correct? |
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Mar 27 |
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Involution $\Rightarrow$ Hermitian & Unitary Thanks @WesonJiang, that's actually a very insightful way to think intuitively about these things. |
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Mar 27 |
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Involution $\Rightarrow$ Hermitian & Unitary Thanks a lot, an amazing answer! |
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Mar 27 |
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Involution $\Rightarrow$ Hermitian & Unitary Thanks, the sudden introduction of all the new names for matrices still confuses me a little. |
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Mar 27 |
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Involution $\Rightarrow$ Hermitian & Unitary Oh, yes, sorry, I added that to the question. Thanks for clearing that up, still, why would that be true? |
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Jan 22 |
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Why is $y = \sqrt{x-4}$ a function? and $y = \sqrt{4 - x^2}$ should be a circle Further reading on wikipedia |
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Jan 19 |
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Limit of a Composite Function Sorry for taking so long, I needed to review the topics before limits, as I felt my knowledge is not deep enough to understand this properly. Is the following then correct? (1) If $f$ is continuous, then we do not need to worry about $g(x)=A$ as $f(A)$ exists and is equal to the limits. (2) In this case, $g(x)$ can never equal to A $\forall x$. (3) If $g$ is strictly monotonous, then $g(x)=A$ only for one point and that point could only be $a$, which we are not considering, therefore $g(x)\neq A$ $\forall x\in D(f)\setminus\{a\}$ |
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Jan 17 |
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Intuition behind convex functions You are right, @HaraldHanche-Olsen. |
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Jan 17 |
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Intuition behind convex functions Thanks all. I should've perhaps mentioned that I did indeed observe the wikipedia picture before, but as it often happens, I wasn't able to make sense of it until somebody wiser points me towards it, saying "look at it, it's simple". @JavaMan I'll try to do that now. |
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Jan 15 |
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Is there an abbreviation for “almost all $x\in X$”? Not attempting to answer the question, but commenting on-topic: I've always liked the visual information quickly conveyed by $\forall$ (something the phrase "for all" just can't do), so in my own notes I've started using $\stackrel{a.}{\forall}$ |
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Jan 15 |
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Definition of Continuity Thanks for the answer. |
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Jan 15 |
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Definition of Continuity Aha! I get it now. It's more of a linguistic problem, actually. In Czech the word "lze" can be understood as both "can only be" and "it is possible to" and the second possibility didn't occur to me. Thanks for clearing that up! |
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Jan 13 |
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Online MathJaX editor I quite like this solution, thanks. (And it's probably the best I can do now) |
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Jan 12 |
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Heine-Borel for reals Actually: about c) if we know that $\alpha$ is in the cover, then we probably don't need to do that. But that goes against what coffeemath said, or so it seems to me. |
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Jan 12 |
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Heine-Borel for reals Here I go: First proof questions. a) How do we know that $\alpha$ is in the cover? b) If we know that $\alpha$ is in the cover, don't we then also know that $[0,\alpha]$ can be covered, thus no need for $a$? c)When we know that $\alpha=1$, then we only need to take the interval $(1-\delta_1,1+\delta_1)$ to cover the whole $[0,1]$ (because we've only covered $[0,1)$ at that point), is that correct? Thanks. |
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Jan 12 |
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Online MathJaX editor @Martin. Thanks together with the sandbox, this could do the job (even if sloppy). However, I have just one last problem, I've tried a number of PDF creators and none of them seem to preserve signs such as $\mathbb{R}$, do you have any ideas what to do about that? |
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Jan 11 |
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Online MathJaX editor If that were to happen, I'd probably open a bottle of champagne or something. |
