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location Cleveland Heights, OH
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seen Jan 2 at 12:05

Professor emeritus at Cleveland State University. I’m a set-theoretic and general topologist with an interest in combinatorics. I’m also interested in linguistics, especially historical linguistics.


May
15
answered Existence of a graph G?
May
15
answered Let $A$ be a matrix sized $p\times p$, where $2\le p$. Using recurrence relations, describe $A^k$.
May
15
revised Let $A$ be a matrix sized $p\times p$, where $2\le p$. Using recurrence relations, describe $A^k$.
added 2 characters in body
May
15
comment Let $A$ be a matrix sized $p\times p$, where $2\le p$. Using recurrence relations, describe $A^k$.
I’ve found this PDF to be a handy quick reference for mathematical symbols.
May
15
comment Let $A$ be a matrix sized $p\times p$, where $2\le p$. Using recurrence relations, describe $A^k$.
You can get $\times$ with \times.
May
15
revised Let $A$ be a matrix sized $p\times p$, where $2\le p$. Using recurrence relations, describe $A^k$.
Fixed LaTeX. Spelling in title.
May
15
comment drawing open balls for the radar screen metric
@Des: The question is internally inconsistent. The unit ball must indeed have radius one, so it’s impossible to draw the unit ball of radius $\frac12$ or $\frac32$. Some part of the question must therefore be in error. It’s most likely that the word unit is the mistake, and that you’re intended to draw the balls of radii $\frac12,1$, and $\frac32$.
May
15
reviewed Approve suggested edit on Riemann integral with intervals?
May
15
comment Does the following graph have a Hamilton circuit?
@Kevin: No, I just tinkered a bit. I started with $1,4,2,5,3,8$ but quickly realized that the $4$ killed off any chance to use the $7$, so I deleted it and considered $1,2,5,3,8$; the rest pretty much wrote itself.
May
15
answered Does the following graph have a Hamilton circuit?
May
15
comment What is $(\operatorname{monad}(0), \leq)$ isomorphic to?
@MettaWorldPeace: I suspect not. It’s consistent that the monad have the same order type as ${}^*\Bbb R$, but it’s also consistent that these two order types by different. You might try to see what you can get out of this paper.
May
15
revised Demonstration using the Pigonhole principle
added 130 characters in body
May
15
comment Demonstration using the Pigonhole principle
@user17762: Ah, right; I forgot that when I added the second example.
May
15
answered Demonstration using the Pigonhole principle
May
15
answered What is $(\operatorname{monad}(0), \leq)$ isomorphic to?
May
15
comment drawing open balls for the radar screen metric
@Des: Since $\min\{1,\|x-y\|\}$ is not a single number, but rather (for fixed $x$) a function of $y$, it doesn’t make sense to say that some ball is bigger than that. Look at the definition of $B\left(x,\frac32\right)$: it’s $\left\{y\in\Bbb R^2:d(x,y)<\frac32\right\}$. What subset of $\Bbb R^2$ is that?
May
15
answered drawing open balls for the radar screen metric
May
15
comment Finitely additive probability measure thats not countably subadditive
@lithiumbarbiedoll: Of course not: it obviously isn’t one. The question doesn’t ask for one.
May
15
answered Transitivity of union of two transitive relations
May
15
comment Confused about combinatorials
@Nick: It’s my best guess at what’s intended when you’re asked for a combinatorial proof here. The term basically means showing that two expressions are equal by showing that they count the same set in two different ways, and that’s what we’re doing here.