The question may seem silly, but I do not find the answer.
For me, the $n-$torus is "an sphere with $n$ holes".
Topologically, this is called the connected sum of $n$ tori, is it right?
What about the $T^n=\overbrace{S^1\times \cdots \times S^1}^{n \,times}$, what is its name and what are its properties?
Do the two surfaces have some relation?
Thank you so much.
Best Answer
What you've described is the n-Torus:
$$ T^n = S^1 \times \dots \times S^1 $$
See the wiki entry: https://en.wikipedia.org/wiki/Torus#n-dimensional_torus