Recent content by bb11
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Graduate Is the Sum of Two Closed Sets in R^n Always Closed?
A+B need not to be closed! The sum of compact sets K_1 and K_2 is compact, and hence closed, as K_1 x K_2 is compact, Sum: R^n x R^n ---> R^n , Sum(x,y)=x+y is continuous, and the image of compact sets is compact under continuous functions. Thus, if you want to have a...