In the context of general relativity and the canonical formulation of the theory, the Hamiltonian constraint is a fundamental equation that arises in the process of quantizing gravity. It plays a key role in the framework known as Hamiltonian formalism or the ADM (Arnowitt-Deser-Misner) formulation of general relativity.
A **Cauchy surface** is a concept used in the context of general relativity and differential geometry, particularly in the study of spacetime. It is a type of hypersurface that has important implications for the determination of the evolution of physical fields and signals in spacetime.
Self-play is a training technique used primarily in artificial intelligence and machine learning, particularly in the development of algorithms for games and strategic decision-making. In self-play, an AI system plays against itself instead of competing against human opponents or other external agents. This approach allows the AI to explore a wide range of strategies and scenarios without the need for external data.
A corrosion inhibitor is a chemical substance that, when added in small amounts to a corrosive environment, significantly reduces the rate of corrosion of metals or alloys. Corrosion is the natural process where metals deteriorate due to reactions with their environment, often involving moisture, oxygen, salts, or acids. Corrosion inhibitors work by various mechanisms, such as: 1. **Surface Film Formation:** Some inhibitors form a protective film on the metal surface, preventing corrosive agents from contacting the metal.
The NLGI (National Lubricating Grease Institute) consistency number is a standardized classification system used to describe the thickness or viscosity of lubricating grease. This classification helps users select the appropriate grease for specific applications by providing a measure of its consistency.
Accumulated Local Effects (ALE) is a statistical technique used primarily in the context of interpreting machine learning models, particularly those that are complex and difficult to understand, such as ensemble methods or neural networks. ALE provides insights into how the predicted outcomes of a model change as individual features (or variables) are varied.
Ludwig Wittgenstein's philosophy of mathematics is primarily presented in his later work, particularly in "Philosophical Investigations" and "Remarks on the Foundations of Mathematics." His approach represents a significant departure from traditional philosophical views of mathematics, emphasizing the role of language, use, and social practices.
The Dominance-Based Rough Set Approach (DRSA) is a methodology used in decision-making processes, particularly within the fields of data mining, machine learning, and multi-criteria decision analysis. It integrates the concepts of rough set theory and dominance relations to handle uncertainty and vagueness in decision-making.
Error-driven learning is a type of learning that emphasizes the importance of errors in the educational process. It involves using mistakes or deviations from desired outcomes as a catalyst for improvement and adaptation. This approach is often applied in various fields, including machine learning, cognitive psychology, and education. Here are some key aspects of error-driven learning: 1. **Feedback Mechanism**: Errors serve as feedback that indicates where a learner or a system has deviated from the expected path.
Exoticism by Ciro Santilli 40 Updated 2025-07-16
Video 1.
Emmenez-moi by Charles Aznavour (1968)
Source. The ultimate ode to exoticism.
An Alias in macOS is a type of shortcut that provides a quick way to access a file, folder, or application without needing to navigate to its original location on your hard drive. When you create an alias, it creates a small file that points to the original item but does not duplicate the content itself. You can create an alias in macOS by right-clicking (or Control-clicking) on an item and selecting "Create Alias" from the context menu.
The Godfather by Ciro Santilli 40 Updated 2025-07-16
www.youtube.com/playlist?list=PLVV0r6CmEsFzCodipONmNiROhYCUWyz_U interview with Walter Murch by Web of Stories. He worked on sound design for all The Godfather films, and tells some interesting details about it. He's just super nice in general otherwise. E.g.:

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