Finite topology, often referred to in the context of finite topological spaces, typically involves the study of topological spaces that have a finite number of points. In a finite topological space, the set of points is limited, which leads to simplified structures and properties compared to infinite topological spaces. ### Key Concepts of Finite Topology: 1. **Finite Set**: A finite topological space has a finite number of elements.
In topology, a **generic point** is a concept used to describe a point that represents a subset of a topological space in a broad or "generic" sense. Specifically, a point \( x \) in a topological space \( X \) is called a generic point of a subset \( A \) of \( X \) if every open set containing \( x \) intersects \( A \) in a non-empty set.
In topology and related fields, an Esakia space is a type of topological space that is associated with the study of certain classes of lattices. Specifically, Esakia spaces arise in the context of modal logic and can be understood in terms of their strong relation to Kripke frames. An Esakia space is characterized by having certain order-theoretic properties that are related to the accessibility relations in modal logic semantics.
The Nagata–Smirnov metrization theorem is a fundamental result in topology that provides conditions under which a topological space can be metrized, meaning that the topology of the space can be derived from a metric. This theorem is particularly relevant for spaces that are compact, Hausdorff, and first-countable.
The term "neighbourhood system" can have different meanings depending on the context. Here are a few interpretations: 1. **Urban Planning and Geography**: In urban planning, a neighbourhood system refers to the arrangement and organization of communities within a larger city or metropolitan area. It encompasses residential areas, commercial zones, parks, and public spaces, and focuses on the interactions and relationships between these components.
Nested interval topology is a specific topology defined on the real numbers \(\mathbb{R}\) based on the concept of nested closed intervals. This topology is generated by a base consisting of the sets that can be formulated using nested sequences of closed intervals.
In the context of topology, a \( G_\delta \) set (pronounced "G delta set") is a subset of a topological space that can be expressed as a countable intersection of open sets.
A Polish space is a concept from the field of topology and descriptive set theory. Specifically, a Polish space is a topological space that is separable (contains a countable dense subset) and completely metrizable (can be endowed with a metric that induces its topology and is complete, meaning every Cauchy sequence converges within the space).
Polyadic space is a concept in the field of mathematical logic and set theory, specifically relating to the study of algebras and their generalizations. It generally refers to structures that generalize the idea of a relational or functional space by considering relations or functions that can take multiple arguments (or "ary" inputs), hence the prefix "polyad-.
The term "Flat Earth" refers to the belief that the Earth is flat, rather than an oblate spheroid, which is the scientifically established understanding. This belief has historical roots dating back to ancient civilizations, but it has been largely discredited by centuries of scientific evidence, including observations from space, satellite imagery, and the principles of physics. Advocates of the Flat Earth theory often assert that mainstream science is misleading and that they have evidence to support their claims.
Interlocking interval topology is a concept in the field of topology, specifically dealing with spaces constructed using intervals that have a particular relationship with one another. Here's a basic overview of the concept: ### Definitions: 1. **Intervals:** In a typical setting (especially in \(\mathbb{R}\)), intervals can be open, closed, or half-open.
In topology, "open" and "closed" maps are concepts that describe certain properties of functions between topological spaces. Here's a brief explanation of each term: ### Open Maps A function \( f: X \rightarrow Y \) between two topological spaces is called an **open map** if it takes open sets in \( X \) to open sets in \( Y \).
In topology and mathematical analysis, an **isolated point** (or isolated point of a set) is a point that is a member of a set but does not have other points of the set arbitrarily close to it.
The Katětov–Tong insertion theorem is a result in the field of topology, particularly in the area of set-theoretic topology. It deals with the properties of certain types of topological spaces, specifically separable metric spaces. The theorem is named after mathematicians František Katětov and David Tong.
The lexicographic order topology on the unit square, which we denote as \( [0, 1] \times [0, 1] \), is based on an ordering of the points in the unit square. In this topology, we define a way to compare points \((x_1, y_1)\) and \((x_2, y_2)\) in the square using the lexicographic order, similar to how words are ordered in a dictionary.
In general topology, various examples illustrate different concepts and properties. Here is a list of significant examples that are commonly discussed: 1. **Discrete Topology**: In this topology, every subset is open. For any set \(X\), the discrete topology on \(X\) consists of all possible subsets of \(X\).
In topology, a space is said to be **locally connected** at a point if every neighborhood of that point contains a connected neighborhood of that point. More formally, a topological space \(X\) is said to be **locally connected** if for every point \(x \in X\) and every neighborhood \(U\) of \(x\), there exists a connected neighborhood \(V\) of \(x\) such that \(V \subseteq U\).
Pinned article: ourbigbook/introduction-to-the-ourbigbook-project
Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
Intro to OurBigBook
. Source. We have two killer features:
- topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculusArticles of different users are sorted by upvote within each article page. This feature is a bit like:
- a Wikipedia where each user can have their own version of each article
- a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.Figure 1. Screenshot of the "Derivative" topic page. View it live at: ourbigbook.com/go/topic/derivativeVideo 2. OurBigBook Web topics demo. Source. - local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
- to OurBigBook.com to get awesome multi-user features like topics and likes
- as HTML files to a static website, which you can host yourself for free on many external providers like GitHub Pages, and remain in full control
Figure 2. You can publish local OurBigBook lightweight markup files to either OurBigBook.com or as a static website.Figure 3. Visual Studio Code extension installation.Figure 5. . You can also edit articles on the Web editor without installing anything locally. Video 3. Edit locally and publish demo. Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension. - Infinitely deep tables of contents:
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact