Table of Contents
What is the significance of topological spaces?
A topological space is the most general type of a mathematical space that allows for the definition of limits, continuity, and connectedness. Other spaces, such as Euclidean spaces, metric spaces and manifolds, are topological spaces with extra structures, properties or constraints.
What’s the point of category theory?
The main benefit to using category theory is as a way to organize and synthesize information. This is particularly true of the concept of a universal property. We will hear more about this in due time, but as it turns out most important mathematical structures can be phrased in terms of universal properties.
What are the applications of category theory?
Category theory has practical applications in programming language theory, for example the usage of monads in functional programming. It may also be used as an axiomatic foundation for mathematics, as an alternative to set theory and other proposed foundations.
What is the difference between metric space and topological space?
Just in terms of ideas: a metric space has a notion of distance, while a topological space only has a notion of closeness. If we have a notion of distance then we can say when things are close to each other. However, distance is not necessary to determine when things are close to each other.
Is category theory the most abstract?
Technically, category theory is not more abstract than the rest of (abstract) algebra. You can derive all other math branches with CT, so yes, it is more abstract. It is “higher level” (in the same sense of programming languages) than other maths. Categories are a bit like graphs in that: they are too general.
Is Hilbert space a topological space?
As a complete normed space, Hilbert spaces are by definition also Banach spaces. As such they are topological vector spaces, in which topological notions like the openness and closedness of subsets are well defined.
What is not a topological space?
A vector space is by nature not a topological space.
What is a convenient category of topological spaces?
The term convenient category of topological spaces is used (e.g. Steenrod 67) for a category of topological spaces nice enough to address many of the needs of working topologists, notably including the condition of being a cartesian closed category. As such, they are examples of nice categories of spaces.
Is a CW complex a product topology?
X imes Y need not be a CW complex in the usual product topology, but it is in the compactly generated topology. The original example of a convenient category of topological spaces is described at
Is TopTop a cartesian closed category?
Top is not cartesian closed. One can characterize the exponentiable spaces, which include all locally compact Hausdorff spaces, but as we saw above, the naive idea of simply cutting down to some of these does not give a good cartesian closed category either, since firstly it need not be complete and cocomplete, and secondly even if Y^X need not be.
What are the Nice categories of spaces?
“Nice categories of spaces” should be thought of as a wider and vaguer term; it really means the category of spaces has “nice” categorical properties for some mathematical purpose at hand. Certainly any convenient category of spaces should be considered a nice category of spaces for the general purposes of algebraic topology.