In mathematics, specifically in the context of topology and set theory, the **derived set** of a given set refers to the set of all limit points (or accumulation points) of that set.
Hyperbolic Dehn surgery is a technique in the study of 3-manifolds, primarily in the field of low-dimensional topology. It involves a process of modifying a given three-dimensional manifold by removing a solid torus and gluing it back in a different way, thus altering the topology of the manifold.
A Klein bottle is a non-orientable surface with no distinct "inside" or "outside." It is a mathematical object in topology, a branch of mathematics concerned with the properties of space that are preserved under continuous transformations.
Particular point topology is a type of topological space characterized by the presence of a designated "particular point" in the space. More formally, let \( X \) be a set, and let \( p \) be a specific element of \( X \). We define a topology \( \tau \) on \( X \) by specifying the open sets in the following way: 1. The empty set \( \emptyset \) is an open set.
Andrew Ranicki is a mathematician known for his contributions to algebraic topology, specifically in the areas of algebraic K-theory and surgical invariants of manifolds. He has also worked on the relationship between topology and mathematical logic. Ranicki is recognized for his research on the use of the exact sequences in algebraic K-theory and for developing techniques that have applications in the classification of manifolds.
Eberhard Hopf (1902–1983) was a renowned German mathematician, known for his contributions to various areas of mathematics, particularly in the field of differential equations and dynamical systems. He is perhaps best recognized for the Hopf bifurcation theorem, which describes how a system's behavior changes as parameters are varied, leading to the emergence of periodic solutions. This theorem is significant in both mathematics and applications across physics, biology, and engineering.
Hiroshi Toda is not a widely recognized figure in popular culture, history, or public information, so there might be multiple individuals with that name. However, one notable Hiroshi Toda is a Japanese researcher known for his work in the field of electrical engineering and information technology. He has been involved in various academic pursuits, including research related to computing and engineering.
Katsuya Eda is a Japanese Roman Catholic priest and theologian. He is known for his work in various areas of theology and has contributed to discussions on topics such as religious education and interfaith dialogue. However, detailed information on his specific achievements or contributions might not be widely available.
Lisa Piccirillo is a mathematician known for her work in the field of topology, specifically in the study of knot theory. She gained significant attention for her research on the Conway knot, where she provided a proof that it is not slice. This was a notable contribution to the field and demonstrated her abilities in addressing complex problems related to knots and their properties. Piccirillo is also recognized for her work in promoting mathematics and encouraging diversity within the field.
Yuli Rudyak is not a widely recognized name in mainstream culture or academia, as of my last knowledge update in October 2023. However, if this is an emerging individual or a specific entity (like a brand, project, or concept) that has gained prominence after that date, I would not have information on it.
Proj construction is likely a reference to "projection construction," which is used in various fields, including computer graphics, engineering, and project management. However, since "Proj construction" could refer to different concepts depending on context, let me outline a few possible interpretations: 1. **Projection Construction in Mathematics/Geometry**: This refers to methods of creating projections of geometric shapes, often to simplify complex visuals or to work within different dimensions.
Minimal logic is a type of non-classical logic that serves as a foundation for reasoning without assuming the principle of explosion, which states that from a contradiction, any proposition can be derived (ex falso quodlibet). In classical logic, contradictions are problematic since they can lead to trivialism, the view that every statement is true if contradictions are allowed.
A rule of inference is a logical rule that describes the valid steps or reasoning processes that can be applied to derive conclusions from premises or propositions. In formal logic, these rules facilitate the transition from one or more statements (the premises) to a conclusion based on the principles of logical deduction. Rules of inference are foundational in disciplines such as mathematics, philosophy, and computer science, especially in areas related to formal proofs and automated reasoning.
In mathematical logic, a **theory** is a formal system that consists of a set of sentences or propositions in a particular language, along with a set of axioms and inference rules that determine what can be derived or proven within that system. The sentences are typically formulated in first-order logic or another formal logical language, and they can express various mathematical statements or properties.
Logical form refers to the abstract structure of statements or arguments that highlights their logical relationships, irrespective of the specific content of the statements. It serves to represent the underlying logic of a statement or argument in a way that clarifies validity, inference, and logical consistency. In linguistics and philosophy, the notion of logical form is often used to analyze natural language sentences to reveal their syntactic and semantic properties.
Plural quantification is a concept in philosophy and linguistics that pertains to how we refer to and quantify plural entities in language and logic. It explores how statements can be made about multiple objects or individuals, often involving considerations of meaning, reference, and the nature of plural terms. In formal logic, plural quantification allows for the expression of propositions that involve multiple objects without needing to enumerate them explicitly.
The Modern Greek Enlightenment refers to a cultural and intellectual movement that took place in Greece during the late 18th and early 19th centuries, coinciding with the broader European Enlightenment. This period was characterized by a renewed interest in classical learning, philosophy, and the sciences, as well as a push for political and social reforms.

Pinned article: 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!
We have two killer features:
  1. 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-calculus
    Articles 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/derivative
  2. 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.
    Figure 2.
    You can publish local OurBigBook lightweight markup files to either https://OurBigBook.com or as a static website
    .
    Figure 3.
    Visual Studio Code extension installation
    .
    Figure 4.
    Visual Studio Code extension tree navigation
    .
    Figure 5.
    Web editor
    . 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.
    Video 4.
    OurBigBook Visual Studio Code extension editing and navigation demo
    . Source.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
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