A **dissipative system** is a system in which energy is not conserved due to the presence of non-conservative forces like friction, viscosity, or other forms of resistance. In these systems, energy is lost, often converted into heat or other forms of energy that are not useful for doing work. This leads to a decrease in the total mechanical energy of the system over time.
A **random compact set** is a concept commonly encountered in the fields of probability theory and convex analysis, particularly in the context of stochastic geometry and the study of random sets. In mathematical terms, a compact set is a subset of a Euclidean space that is closed and bounded. This means that the set contains all its limit points and can fit within a large enough closed ball in the space.
The Hartman–Grobman theorem is a result in the field of differential equations and dynamical systems, named after mathematicians Philip Hartman and Robert Grobman. The theorem provides a powerful tool for analyzing the local behavior of nonlinear dynamical systems near equilibrium points.
In chemistry, "equilibrium" refers to a state in a chemical reaction where the concentrations of reactants and products remain constant over time. This state occurs when the forward and reverse reactions proceed at the same rate, resulting in no net change in the concentrations of the substances involved. Key aspects of chemical equilibrium include: 1. **Dynamic Nature**: Equilibrium is dynamic, meaning that while the concentrations remain constant, the reactions continue to occur in both directions at equal rates.
The Wohl model is a theoretical framework used in the field of chemistry and materials science, particularly for studying phase transitions and the thermodynamic behavior of systems. It is often associated with the way certain materials behave under varying conditions of temperature and pressure.
An anticyclonic storm is a type of weather system characterized by high atmospheric pressure at its center. In meteorology, "anticyclone" refers to a region where the atmospheric pressure is significantly higher than that of the surrounding areas. In an anticyclonic system, air descends and spreads outward, leading to generally clear and stable weather conditions.
The Ridiculously Resilient Ridge (RRR) refers to a persistent high-pressure system in the atmosphere that can influence weather patterns, particularly in the western United States. This phenomenon gained attention starting around 2013 when it became more prominent in discussions about drought conditions and climate patterns in California and the surrounding areas. The RRR is characterized by unusually high atmospheric pressure that can remain stationary for extended periods, leading to dry, warm conditions.
A post-tropical cyclone is a storm system that has lost its tropical characteristics, typically due to cooler sea surface temperatures or interaction with land. While it may still retain some features of a tropical system, such as a well-defined circulation, it no longer meets the criteria to be classified as a tropical storm or hurricane. Post-tropical cyclones can take on a variety of forms, including extratropical cyclones, which are characterized by fronts and a temperature gradient.
The Exterior Angle Theorem is a fundamental principle in triangle geometry that relates the measures of an exterior angle of a triangle to the measures of its remote interior angles. The theorem states that: In any triangle, the measure of an exterior angle is equal to the sum of the measures of the two opposite (or remote) interior angles. To illustrate, consider triangle ABC where angle C is an exterior angle formed by extending side AC.
Magnetic declination, also known as magnetic variation, is the angle between magnetic north (the direction a compass points) and true north (the geographic north pole) at a given location on the Earth's surface. This angle is measured in degrees east or west from true north. Because the Earth's magnetic field is not uniform, magnetic declination varies depending on where you are located. It can change over time due to shifts in the Earth’s magnetic field.
In geometry, the term "parallel" refers to two or more lines or planes that are the same distance apart at all points and do not meet or intersect, no matter how far they are extended. This property is fundamental in understanding the behavior of lines within Euclidean geometry. ### Key Properties of Parallel Lines: 1. **Equidistant**: Parallel lines maintain a constant distance from each other, meaning the distance between them remains consistent along their entire length.
In category theory, a Kleisli category is a construction that allows you to work with monads in a categorical setting. A monad, in this context, is a triple \((T, \eta, \mu)\), where \(T\) is a functor and \(\eta\) (the unit) and \(\mu\) (the multiplication) are specific natural transformations satisfying certain coherence conditions.
Differential Galois theory is a branch of mathematics that studies the symmetries of solutions to differential equations in a manner analogous to how classical Galois theory studies the symmetries of algebraic equations. ### Key Concepts: 1. **Differential Equations**: These are equations that involve unknown functions and their derivatives. The solutions to these equations can often be quite complex.
Abelian group theory is a branch of abstract algebra that focuses on the study of Abelian groups (or commutative groups). An **Abelian group** is a set equipped with an operation that satisfies certain properties: 1. **Closure**: For any two elements \( a \) and \( b \) in the group, the result of the operation (usually denoted as \( a + b \) or \( ab \)) is also in the group.
The Verschiebung operator, also known as the shift operator, is a mathematical operator used in various fields, including quantum mechanics and functional analysis. The term "Verschiebung" is German for "shift," and the operator is typically denoted by \( S \). In the context of quantum mechanics, for example, the shift operator can shift states in a Hilbert space.
The Suzuki Group refers to a collection of companies and entities that are associated with Suzuki Motor Corporation, a Japanese multinational corporation known primarily for its automobiles, motorcycles, all-terrain vehicles, and other products. Founded in 1909 by Michio Suzuki, the company originally started as a manufacturer of looms before transitioning into the automotive sector in the 1950s. Suzuki Motor Corporation is recognized for its small cars, compact vehicles, and motorcycle production.
In the context of lattice theory, particularly in the fields of mathematics and physics, a dual lattice is a concept that arises in the study of periodic structures, such as crystals or in the theory of vector spaces. 1. **Lattice Definition**: A lattice typically refers to a discrete subgroup of Euclidean space that is generated by a finite set of basis vectors.
A **modular lattice** is a type of lattice in order theory with a specific property regarding its elements. A lattice is an algebraic structure that consists of a set equipped with two binary operations, meet ( ∧ ) and join ( ∨ ), which satisfy certain axioms. Lattices can be visualized as a partially ordered set (poset) where every two elements have a unique supremum (join) and infimum (meet).
The Lumer–Phillips theorem is a result in functional analysis, particularly within the context of operator theory. It provides conditions under which a linear operator generates a strongly continuous one-parameter semigroup (also known as a strongly continuous semigroup of operators) on a Banach space. The theorem is named after the mathematicians Fredric Lumer and William Phillips, who contributed to its development.
The Paris–Harrington theorem is a result in the field of mathematical logic and combinatorics, specifically in the area of set theory and the study of large cardinals. It is a form of combinatorial principle that exemplifies the limits of certain deductive systems, particularly in relation to the axioms of Peano arithmetic and other standard set theories.

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