Henry Shearman
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 May 28 comment Why do we need $\sup$ and $\inf$ when we have $\max$ and $\min$. Consider the maximum value for a function for which the range is $[0,b)$. Mar 9 awarded Popular Question May 3 comment Characterisation of the spectrum of certain unitary representations on $L^2(G)$ If it helps, I am mostly concerned with translation operators such as the left and right regular representations. May 3 revised Characterisation of the spectrum of certain unitary representations on $L^2(G)$ edited title May 3 asked Characterisation of the spectrum of certain unitary representations on $L^2(G)$ Dec 5 awarded Yearling Feb 20 comment Proof that $n^3+2n$ is divisible by 3 Try expanding $(n+1)^3 + 2(n+1)$ and note that you have assumed $n^3 +2n$ is assumed divisible by 3. What does this tell you about the $n+1$th case? Jan 31 revised prove for all $n\geq 0$ that $3 \mid n^3+6n^2+11n+6$ Latex Edit Jan 31 suggested approved edit on prove for all $n\geq 0$ that $3 \mid n^3+6n^2+11n+6$ Jan 31 comment prove for all $n\geq 0$ that $3 \mid n^3+6n^2+11n+6$ Induction will be handy here. Jan 25 revised Cauchy's convergence criterion added 32 characters in body Jan 25 answered Cauchy's convergence criterion Jan 24 comment Alternate definition of closed set in $\mathbb{R}$ @JonasMeyer: It's a bit of an abuse of the function notation (or maybe just wrong). I was trying to say that some sort of structure should be shown with $\mathbb{R}$ in the space where the dot was placed just so the community knows whether the OP is dealing in a metric space or a strictly topological space. Sorry for the confusion/bad notation. Jan 24 comment Alternate definition of closed set in $\mathbb{R}$ Yes, the standard topology on $\mathbb{R}$ is what would be assumed. I was more implying that it should have been stated that it was a metric space. The balls make that obvious here though. Jan 24 comment Alternate definition of closed set in $\mathbb{R}$ It helps if you specify the topological structure of $(\mathbb{R},\cdot)$ in the question. Jan 23 comment Convergence of $\sum_{n=1}^\infty\frac{1}{2\cdot n}$ You'll have a hard time with that one. If you factor out the half, then you are left with the harmonic series. Jan 23 comment Closure of $A \subset \mathbb{R}$ Ah yes, sorry about that. To ammend the proof strategy that I have provided, you must assume that an element of $bdry(A)$ is either a limit point or an isolated point of both $A$ and $X\backslash A$ and then argue for both cases that it cannot be an interior point. Jan 23 comment Closure of $A \subset \mathbb{R}$ $bdry(A)$ is the set of limit points of $A$ that are also limit points of $X\backslash A$. Then you need to show that a boundry point is an element of $\bar{A}$ that cannot be an interior point. Hence from $bdry(A) = \bar{A}\backslash int{A}$, the result follows. Jan 20 comment Linear operator's linearity The $z^2$ vanishes with the choice of $a$. Jan 20 comment Linear operator's linearity Yes, don't mind me. I confused myself for a second.