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location Cleveland Heights, OH
age 66
visits member for 3 years, 7 months
seen 1 min ago

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.


Sep
3
answered Continuity and Compactness
Sep
3
answered How to show $\sqrt{4+2\sqrt{3}}-\sqrt{3} = 1$
Sep
3
comment Incredibly obvious answer isn't obvious?
It’s the last of the six options.
Sep
3
awarded  Enlightened
Sep
3
comment $d(f,g)=\sup\{\lvert f(x)-g(x)\rvert : x\in[0,1]\}$
@Trancot: You definitely need to understand why the triangle inequality holds in it in order to see why it holds here.
Sep
3
comment $d(f,g)=\sup\{\lvert f(x)-g(x)\rvert : x\in[0,1]\}$
@Trancot: Have you finished the previous question yet?
Sep
3
comment How can I prove $f_M(x) = \min(f(x),M)$ is lower semi-continuous?
There are a couple of different (though equivalent) ways to define lower semicontinuity; which one are you using?
Sep
3
revised Openness in a Subset of $\mathbb{R}$ in Metric Spaces: An Analysis in Topological Equivalence
Improved formatting.
Sep
3
answered Middle school number theory
Sep
3
answered $d(f,g)=\sup\{\lvert f(x)-g(x)\rvert : x\in[0,1]\}$
Sep
3
revised Cantor's Set Has No Intervals
added 14 characters in body
Sep
3
answered A Particular Metric: $(\mathbb{R}^2,d_2)$
Sep
3
answered Cantor's Set Has No Intervals
Sep
3
answered limit of a recursive sequence:2
Sep
3
revised Deriving a recurrence relation
Improved formatting.
Sep
3
comment Ancient babylonian geometry
@D-Man: They lacked our algebraic notation for writing those formulas, but they knew the Pythagorean theorem and a number of basic area and volume formulas, including those for triangles and rectangles.
Sep
3
answered Ancient babylonian geometry
Sep
3
comment Reference request : Intro to geometry/topology for beginners
I added geometry to your title, because I was misled by the original version. What you want is at best peripheral to what I think of as topology. If you had wanted general topology, I’d have suggested the out of print Theory and Examples of Point-Set Topology by John Greever, provided that you could find copies: it’s a Moore method text, leaving most of the proofs to the student, which makes it very good for a readings course. (As a freshman I took that course from the author.)
Sep
3
revised Reference request : Intro to geometry/topology for beginners
Made title more accurate.
Sep
3
answered Probability-How many ways can 5 finalists be ranked from 1st place to 5th place?