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Is the image of a closed set under a contiuous function closed?
From Mathematics Is A Science
Jump to navigationJump to searchQuestion: Is the image of a closed set under a continuous function always closed?
Answer: No.
Why: Consider the projection of the graph of $y = \frac{1}{x}$ onto the $x$-axis, or simply the inclusion of an open interval into ${\bf R}$ (it is closed in itself!)...
Also. is the image of an open set under a continuous function open?
