A **hemicompact space** is a type of topological space that is defined based on the properties of its open cover. Specifically, a topological space \( X \) is called hemicompact if every open cover of \( X \) has a countable subcover that is also locally finite. To unpack this a little further: - **Open Cover**: A collection of open sets whose union contains the entire space \( X \).
Nikolai Aleksandrovich Kozyrev (1908-1983) was a Soviet astronomer and physicist, known primarily for his work in astrophysics and for his controversial theories on the nature of time and space. He became notable for his research on the potential for physical effects arising from the gravitational influence of celestial bodies and for his hypothesis concerning the relationship between time and physical processes.
In mathematics, particularly within the field of topology, a **topological property** is a property that is preserved under homeomorphisms. A homeomorphism is a continuous function between topological spaces that has a continuous inverse. Because of this, topological properties are often called "topological invariants." Some common examples of topological properties include: 1. **Connectedness**: A space is connected if it cannot be divided into two disjoint non-empty open sets.
An ultraconnected space is a concept in topology—a branch of mathematics that studies the properties of space that are preserved under continuous transformations. A topological space \( X \) is called **ultraconnected** if it is non-empty and any two open sets in \( X \) intersect non-trivially, meaning that the intersection of any two non-empty open sets is not empty.
Harry Grindell Matthews (1886–1965) was a British inventor and entrepreneur known for his work in the field of early radio technology. He gained notoriety for developing various inventions related to radio communications and wireless technology during the early 20th century. Matthews is particularly remembered for his attempts to create devices that could transmit and receive wireless signals over long distances, including efforts to develop a wireless telephone.
Alfred Lawson was an American aviation pioneer, businessman, and inventor active in the early 20th century. He is perhaps best known for developing the Lawson Airliner, which he promoted as a revolutionary aircraft design. Lawson also founded the Lawson Aviation Corporation and was involved in various ventures throughout his career, including efforts to advance the field of aviation and promote air travel. In addition to his work in aviation, Lawson was also known for his eccentric ideas and beliefs, which sometimes garnered criticism.
As of my last knowledge update in October 2023, I don't have any specific information on "Arthur Patschke." It’s possible that he is not a widely known public figure or his relevance may be limited to specific fields or locales.
The "Gunslinger effect" typically refers to a phenomenon observed in competitive environments, particularly in fields like sports or gaming, where individuals or teams make aggressive decisions or take high-risk actions in response to pressure or to compensate for perceived shortcomings. This term can also appear in contexts like trading or investments, where participants might overreach or take bold risks after a series of losses or failures.
Stefan Marinov was a Bulgarian-born physicist and entrepreneur known for his work in the fields of gravitational physics and alternative energy. Born in 1933, he emigrated to the United States where he became involved in various scientific endeavors. Marinov is perhaps best known for his controversial claims regarding the nature of gravity and his experiments aimed at demonstrating the effects of gravitational waves.
Psychoacoustics is the study of the psychological and physiological responses associated with sound. It explores how humans perceive, interpret, and react to various aspects of sound, including pitch, loudness, timbre, and spatial location. This interdisciplinary field combines principles from psychology, acoustics, and neuroscience to understand the relationship between sound waves and human perception.
The odor detection threshold is the minimum concentration of a substance that can be detected by the human sense of smell. It is the lowest level at which a particular odor can be perceived, and it can vary widely depending on the substance, the individual's sensitivity, and environmental factors. In scientific studies, the odor detection threshold is often quantified in terms of parts per million (ppm), milligrams per cubic meter (mg/m³), or other relevant units, depending on the context.
A second-order stimulus, also known as a conditioned stimulus, refers to a stimulus that has become associated with an unconditioned stimulus through a process called second-order conditioning. In classical conditioning, an unconditioned stimulus (US) naturally elicits a response (unconditioned response, UR) without prior learning, such as food causing salivation in dogs.
The Stroop effect is a psychological phenomenon that demonstrates the interference in reaction times when the processing of one type of information is disrupted by conflicting information from another type. It is most commonly illustrated through the Stroop color-naming task. In a typical Stroop task, participants are presented with words that are names of colors (e.g., "red," "blue," "green") printed in ink that is either congruent (e.g.
Pythagorean philosophy, attributed to the ancient Greek philosopher Pythagoras (c. 570–495 BCE) and his followers, is a rich and multifaceted system of thought that blends mathematics, mysticism, ethics, and religion. Here are some key components of Pythagorean philosophy: 1. **Mathematics and Numbers**: Pythagoreans believed that numbers were the fundamental reality of the universe and that they held metaphysical significance.
A Lambert series is a type of mathematical series named after the mathematician Johann Heinrich Lambert. It is defined in a particular form, usually involving a power series with specific coefficients. The general form of a Lambert series can be expressed as: \[ \sum_{n=1}^{\infty} \frac{n q^n}{1 - q^n} \] where \( |q| < 1 \) is a complex variable.
A conditional quantifier is a type of logical quantifier that expresses a condition under which a statement is true. In formal logic, quantifiers are used to indicate the scope of a term and can significantly change the meaning of statements. The most common quantifiers are: 1. **Universal Quantifier (∀)**: This asserts that a statement is true for all elements in a specified set.
The Lindström quantifier is a type of quantifier used in mathematical logic, particularly in model theory and infinitary logic. It generalizes standard logical quantifiers like the existential quantifier (∃) and universal quantifier (∀) in a way that allows for the expression of more complex properties than those expressible in first-order logic. The Lindström quantifiers can be seen within the context of the study of logical languages that allow for infinite conjunctions and disjunctions.
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!
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 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. - 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





