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visits member for 2 years, 10 months
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19h
comment Why does a covering map has the injective induced homomorphism?
I think it's in section 53 or something? Just search for covering spaces. It'll be in that general vicinity.
19h
revised How to prove a subgroup is normal?
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19h
comment On Farkas's Lemma and Existence of a particular solution
In what sense are you attributing $<$ for vectors?
19h
revised On Farkas's Lemma and Existence of a particular solution
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19h
comment Measure Theory Problems
Show that Borel sets in $\sigma_X(\mathcal{E})\cap A$ are Borel sets in $\sigma_A(\mathcal{E}\cap A)$.
19h
comment Measure Theory Problems
What have you tried?
19h
revised Write sums in factorial form.
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19h
comment Is Physics really a rigorous subject?
@user170039 His point is more about the axioms of classical mechanics and quantum mechanics, not about the dynamics contained therein. Classically, we can measure position and velocity simultaneously to arbitrarily fine degree; quantum mechanically, the Heisenberg uncertainty principle tells us that we can't know either exactly without completely losing the information about the other. It is true that for certain classes of potentials, the quantum mechanical dynamics give rise to classical dynamics via expectations but that's a different problem than what he meant.
19h
comment Why does a covering map has the injective induced homomorphism?
Check out Munkres. I rather like his treatment of these topics (it's very, very clear).
19h
comment Looking for differentiable function $f:\mathbb R \to \mathbb R$ whose derivative is nowhere continuous
This is a pretty deep question and relates to Baire spaces and $G_{\delta}$ sets. See this thread which explains it very, very well: math.stackexchange.com/questions/292275/… In some sense, this "almost everywhere" behavior is more or less what we naturally think of when we think of "nice" functions so it isn't surprising that it is very difficult to come up with examples where the derivative is nowhere continuous.
19h
revised Limit of the function: x if x is rational and -x if x is irrational
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20h
comment Find a value for “c”
@Bryce You're very welcome :)
20h
comment Find a value for “c”
@Bryce That's exactly right.
20h
comment Find a value for “c”
@HenningMakholm Definitely. I didn't want to overcomplicate things but it's good advice.
20h
comment Prove that if $p\mid(aq)^2$ and $(a,p) = 1$ then $p = q$ where $p,q$ are primes.
Also is $p$ assumed to be prime..? You need to add all details.
20h
comment Find a value for “c”
Well remember, you need $\dfrac{1}{y}$ inside, not $\dfrac{2c}{y}$ to get $e$...
20h
comment Prove that if $p\mid(aq)^2$ and $(a,p) = 1$ then $p = q$ where $p,q$ are primes.
I think you mean to say that $p\mid q$ in your title, not $p=q$.
20h
answered Find a value for “c”
20h
comment Prove a functions is injective
You may want to apply induction here (since you're supposed to be writing a proof, not just stating facts).
20h
revised Prove a functions is injective
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