Convergence in the product and box topology

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SUMMARY

The sequence of functions {f_n} defined from the natural numbers N to the real numbers R converges to the function f(s)=0 for s≥1 in the product topology of R^N. However, it does not converge in the box topology of R^N. This conclusion is based on the definitions of convergence in both topologies, where the product topology allows for convergence in a coordinate-wise manner, while the box topology requires uniform convergence across all coordinates.

PREREQUISITES
  • Understanding of sequences of functions and their convergence.
  • Knowledge of product topology and box topology definitions.
  • Familiarity with the Cartesian product of topological spaces.
  • Basic concepts of real analysis, particularly limits and continuity.
NEXT STEPS
  • Study the definitions and properties of product topology in detail.
  • Explore the characteristics of box topology and its implications for convergence.
  • Investigate examples of function sequences and their convergence in different topologies.
  • Learn about uniform convergence and its relation to various topological spaces.
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Mathematicians, students of topology, and anyone studying real analysis who seeks to understand the nuances of convergence in different topological frameworks.

calvin22
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Hi. Can I have some help in answering the following questions? Thank you.

Let {f_n} be a sequence of functions from N(set of natural numbers) to R(real nos.) where
f_n (s)=1/n if 1<=s<=n
f_n (s)=0 if s>n.
Define f:N to R by f(s)=0 for every s>=1.
a) Does {f_n} (n=1 to inf) converge to f in the R^N (cartesian product) endowed with the product topology?
b) when endowed with the box topology?

Thanks again.
 
Last edited:
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Of course you can can get help, but first tell us what you have tried. The least you can do is trying to come up with some relevant facts about the box and product topologies (such as their definitions, what it means for a sequence to converge in them, and the like).
 

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