**Theorem** $S^{n-1}$ disconnects $S^n$ into two open connected components, which have $S^{n-1}$ as frontier.   
  
>In $R^3$, if we replace sphere of standard torus with genus $g\geq1$, we may have "The Jordan-Brouwer Separation Theorem" intuitively. Then what happens when we replace topological sphere of topology torus with genus $g\geq1$?  
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>We have $T^n$ in $R^{n+1}$, so do we have the same theorem?
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>What is the situation ahout manifold?
  
**Theorem** $H_k(S^n-S^r)=R,k=n-r-1$.  
>Does this theorem have the corresponding generalization?