Error in Book? Is it the Box Topology?

In summary, the conversation discusses the definition of the product topology on Cartesian products of topological spaces. The speaker questions whether the given definition is actually for the product topology or the box topology. Another participant clarifies that for finite products, the two topologies coincide and provides an example to illustrate this. The conversation ends with an agreement that the product topology and box topology are equivalent for finite products.
  • #1
Kreizhn
743
1
Hey,

I'm reading through a book and have come across something that seems like an obvious error to me. The books says

If [itex] (X,T_X) [/itex] and [itex] (Y,T_Y) [/itex] are topological spaces, there's a standard way to define a topology on the Cartesian product [itex] X \times Y[/itex]. If we let
[tex] \mathbb B = \{ O_X \times O_Y : O_X \in T_X, O_Y \in T_Y \} [/tex]
then the topology generated by this basis is called the product topology on [itex] X \times Y [/itex]

Now it's been a long time since I've done any topology, but isn't this the box topology rather than the product topology? I just want to make sure I'm not going crazy.
 
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  • #2
I think the product topology and box topology coincide for finite products. If you are looking at the space X x Y in particular, then the product topology is generated by the set

[tex]\{ O_X \times Y :O_X \in T_X \} \cup \{X \times O_Y:O_Y \in T_Y \} [/tex]

Finite intersections of these sets are open as well. In particular,

[tex](O_X \times Y) \cap (X \times O_Y) = O_X \times O_Y[/tex]

is open.
 
  • #3
Thanks.

I think you're right. Planetmath says that they coincide when the index set is finite.
 

1. What is the Box Topology?

The Box Topology, also known as the product topology, is a way of defining a topology on a Cartesian product of two or more topological spaces. It is generated by open sets that are products of open sets in each of the individual spaces.

2. How does the Box Topology differ from other topologies?

The Box Topology differs from other topologies, such as the standard Euclidean topology, in that it allows for more flexibility in defining open sets. Unlike the Euclidean topology, where open sets are defined by open intervals, the Box Topology allows for open sets that are products of open intervals in each of the individual spaces.

3. What is meant by "Error in Book" in relation to the Box Topology?

"Error in Book" refers to a potential mistake or inaccuracy in a book or publication that discusses the Box Topology. This could be in the form of a typo, incorrect definition, or a flawed proof.

4. How can I identify and correct an error in a book discussing the Box Topology?

If you believe you have found an error in a book discussing the Box Topology, the first step is to carefully check your own understanding and make sure you are interpreting the material correctly. If you are confident that there is an error, you can reach out to the author or publisher to report it. You can also consult with other experts in the field to confirm the error and discuss potential corrections.

5. Are there any common errors or misconceptions related to the Box Topology?

Yes, there are a few common errors and misconceptions related to the Box Topology. One common mistake is confusing the Box Topology with the product topology on the Cartesian product of two topological spaces. Another misconception is that the Box Topology is always finer than the product topology, when in fact this is only true for finite products. It is important to carefully study and understand the definitions and properties of the Box Topology to avoid these errors.

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