Exercise 4.12

Exercise 12: Suppose f is a uniformly continuous mapping of a metric space X into a metric space Y , and suppose g is a uniformly continuous mapping of Y into a metric space Z . Then show that g f is a uniformly continuous mapping of X into Z .

Answers

Let 𝜀 > 0 . Then there is η > 0 such that d Z ( g ( x ) , g ( y ) ) < 𝜀 if d Y ( x , y ) < η . There is also δ > 0 such that d Y ( f ( x ) , f ( y ) ) < η if d X ( p , q ) < δ . Hence if d X ( p , q ) < δ , then d Z ( g ( f ( p ) ) , g ( f ( q ) ) ) < 𝜀 , so g f is uniformly continuous.

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2023-08-07 00:00
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