Jouef is a brand that specializes in model trains and railway accessories. Founded in France in 1950 by entrepreneur Joseph (Jouef being a play on his name), the company initially produced clockwork trains before transitioning to electric model trains. Jouef is known for its high-quality HO scale models, which have been popular among railway enthusiasts for decades.
Kurt Becker KG is a company based in Germany that specializes in the development, production, and distribution of high-quality packaging solutions, primarily for the food sector. The company is well-regarded for its innovative packaging designs and its commitment to sustainability and environmental responsibility. They may offer various products, including containers, trays, and other packaging materials tailored to meet the needs of different industries.
Majorette is a toy manufacturer known primarily for its die-cast model vehicles. Founded in 1961 in France, Majorette initially focused on creating miniature cars and trucks, but over the years expanded to include a wide range of vehicles including emergency services, construction vehicles, and more. The brand is particularly popular for its attention to detail, quality, and playability, often featuring realistic designs and functional elements such as working parts or movable components.
Mercury is a toy manufacturer known for producing various types of toys, including model kits, action figures, and other playthings. The company gained recognition for its high-quality products, often focused on themes such as vehicles, robots, and other popular culture elements. Mercury has been particularly noted for its collectible items and intricate detailing, appealing to both children and adult collectors.
Muky can refer to different things depending on the context. It may be a brand name, a social media platform, or even a specific cultural reference.
Differential geometry is a field of mathematics that studies the properties and structures of differentiable manifolds, which are spaces that locally resemble Euclidean space and have a well-defined notion of differentiability. It combines techniques from calculus and linear algebra with the abstract concepts of topology. Key areas and concepts in differential geometry include: 1. **Manifolds**: These are the central objects of study in differential geometry.
Differential geometry of surfaces is a branch of mathematics that studies the properties and structures of surfaces using the tools of differential calculus and linear algebra. It focuses on understanding the geometric characteristics of surfaces embedded in three-dimensional Euclidean space (though it can extend to surfaces in higher-dimensional spaces).
Finsler geometry is a branch of differential geometry that generalizes the concepts of Riemannian geometry. While Riemannian geometry is based on the notion of a smoothly varying inner product that defines lengths and angles on tangent spaces of a manifold, Finsler geometry allows for a more general structure by using a norm on the tangent spaces that need not be derived from an inner product.
Symplectic geometry is a branch of differential geometry and mathematics that deals with symplectic manifolds, which are even-dimensional manifolds equipped with a closed non-degenerate differential 2-form known as a symplectic form. This structure is pivotal in various areas of mathematics and physics, particularly in classical mechanics.
In mathematics, particularly in the context of differential geometry and topology, a **connection** refers to a way of specifying a consistent method to differentiate vector fields and sections of vector bundles. It essentially allows for the comparison of vectors in different tangent spaces and enables the definition of notions like parallel transport, curvature, and geodesics within a manifold.
The ADHM construction, which stands for Atiyah-Drinfeld-Hitchin-Manin construction, is a mathematical framework used in theoretical physics and geometry, particularly in the study of instantons in gauge theory. It is a method for constructing solutions to the self-duality equations of gauge fields in four-dimensional Euclidean space, which are fundamental in the study of Yang-Mills theory.
The Deformed Hermitian Yang–Mills (dHYM) equation is a modification of the classical Hermitian Yang–Mills (HYM) equations, which arise in the study of differential geometry, algebraic geometry, and mathematical physics, particularly in the context of string theory and stability conditions of sheaves on complex manifolds.
The Atiyah Conjecture is a notable hypothesis in the fields of mathematics, specifically in algebraic topology and the theory of operator algebras. It was proposed by the British mathematician Michael Atiyah and concerns the relationship between topological invariants and K-theory. The conjecture primarily asserts that for a certain class of compact manifolds, the analytical and topological aspects of these manifolds are intimately related.
The Björling problem is a classical problem in the field of differential geometry, particularly in the study of surfaces. It involves the construction of a surface that is defined by a given curve and a specified normal vector field along that curve. More formally, the Björling problem can be described as follows: 1. **Input Specifications**: - A smooth space curve \(C(t)\) in \(\mathbb{R}^3\) (parametrized by \(t\)).
Bochner's formula is a result in differential geometry that relates to the properties of the Laplace operator on Riemannian manifolds. Specifically, it provides a way to express the Laplacian of a smooth function in terms of the geometry of the manifold.
Calibrated geometry is a concept in differential geometry that deals with certain types of geometric structures, specifically those that can be associated with calibration forms. A calibration is a differential form that can be used to define a notion of volume in a geometric setting, helping to identify and characterize minimal submanifolds.
Chern's conjecture in the context of affine geometry is a statement related to the existence of certain geometric structures and their properties. Specifically, it deals with the curvature of affine connections on manifolds. Chern, a prominent mathematician, formulated this conjecture in the realm of differential geometry, particularly focusing on affine differential geometry. Affine geometry studies properties that are invariant under affine transformations (i.e., transformations that preserve points, straight lines, and planes).
A Courant algebroid is a mathematical structure that arises in the study of differential geometry and mathematical physics, particularly in the context of higher structures in geometry and gauge theory. It is a generalization of a Lie algebroid and incorporates the notions of both a Lie algebroid and a symmetric bilinear pairing.
A **Conformal Killing vector field** is a special type of vector field that characterizes the symmetry properties of a geometric structure in a conformal manner. Specifically, a vector field \( V \) on a Riemannian (or pseudo-Riemannian) manifold is called a conformal Killing vector field if it satisfies a particular condition related to the metric of the manifold.
The term "Connection form" can refer to different concepts depending on the context. Here are a few interpretations: 1. **Mathematical Context**: In differential geometry, a connection form is a mathematical object that describes how to "connect" or compare tangent spaces in a fiber bundle. It is often associated with the notion of a connection on a principal bundle or vector bundle, which allows for the definition of parallel transport and curvature.

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