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

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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.
 
A sphere as topological manifold can be defined by gluing together the boundary of two disk. Basically one starts assigning each disk the subspace topology from ##\mathbb R^2## and then taking the quotient topology obtained by gluing their boundaries. Starting from the above definition of 2-sphere as topological manifold, shows that it is homeomorphic to the "embedded" sphere understood as subset of ##\mathbb R^3## in the subspace topology.

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