Understanding // in the Hint for Showing Numbers of Form ±m√2/n Are Dense

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The discussion centers on clarifying the meaning of the symbol "//" in the context of a mathematical hint regarding the density of numbers of the form ±m√2/n. Participants suggest that "//" likely represents division, indicating that one should find a rational number in the interval (x/√2, y/√2) to demonstrate the density of the specified irrational numbers. This interpretation aligns with the goal of showing that multiplying a rational by √2 yields a real number within the desired interval. The conversation emphasizes the importance of understanding notation in mathematical proofs. Overall, the hint is aimed at establishing the density of certain irrational numbers.
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Hello,

Please, someone, explain what the // in the hint below stands for:

"Show that the numbers of the form
±m√2/n
for m, n ∈ N are dense."

Hint:
"To find a number in (x, y), find a rational in (x//√2, y//√2). Conclude from this that the set of
all (irrational) numbers of the form ±m√2/n is dense."

Thank you in advance.
 
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strobeda said:
Hello,

Please, someone, explain what the // in the hint below stands for:

"Show that the numbers of the form
±m√2/n
for m, n ∈ N are dense."

Hint:
"To find a number in (x, y), find a rational in (x//√2, y//√2). Conclude from this that the set of
all (irrational) numbers of the form ±m√2/n is dense."

Thank you in advance.

I think it's a misprint for division, since if you take a rational in (x/\sqrt{2},y/\sqrt{2}) and multiply it by \sqrt{2} you indeed get a real number in (x,y).
 
I suspected that, but I didn't want to go astray trying a wrong tack in case I was just ignorant of the symbol.

Thank you very much, pasmith.
 
We all know the definition of n-dimensional topological manifold uses open sets and homeomorphisms onto the image as open set in ##\mathbb R^n##. It should be possible to reformulate the definition of n-dimensional topological manifold using closed sets on the manifold's topology and on ##\mathbb R^n## ? I'm positive for this. Perhaps the definition of smooth manifold would be problematic, though.

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