Mauritius, like many countries, primarily uses the metric system for most measurements, including length (meters), weight (kilograms), and volume (liters). However, some traditional units may still be in use informally in various contexts, particularly in agriculture or cooking.

TODO understand more intuitively how that determines if a reaction happens or not.

At least from the formula we see that:

A prototypical example of reaction that is exothermic but does not happen at any temperature is combustion.

Somalia uses a combination of both traditional Somali units of measurement and the metric system, which is the official system of measurement in the country. Here are some of the traditional Somali units of measurement: 1. **Length:** - **Courage (cag)**: A traditional unit of length, often refers to a person's height or stature. - **Fool**: A unit that can refer to the length of a piece of string or rope, often about a foot.

TODO can anything interesting and deep be said about "why phase transition happens?" physics.stackexchange.com/questions/29128/what-causes-a-phase-transition on Physics Stack Exchange

Marcel J. E. Golay was a prominent figure known for his contributions to the field of engineering, particularly in signal processing and the design of codes and systems for communication. He is perhaps best recognized for the "Golay codes," which are a pair of error-correcting codes that are optimal for certain types of applications. These codes have applications in various fields, including telecommunications and computer science.

This section is more precisely about classical mechanics.

The idea tha taking the limit of the non-classical theories for certain parameters (relativity and quantum mechanics) should lead to the classical theory.

It appears that classical limit is only very strict for relativity. For quantum mechanics it is much more hand-wavy thing. See also: Subtle is the Lord by Abraham Pais (1982) page 55.

See also: existence and uniqueness of solutions of partial differential equations.

On December 19, 2025 a bet was revealed between two DeepMind guys that one of them would have a Lean proof to the problem:

Originally it was likely created to study constrained mechanical systems where you want to use some "custom convenient" variables to parametrize things instead of global x, y, z. Classical examples that you must have in mind include:lagrangian mechanics lectures by Michel van Biezen (2017) is a good starting point.

When doing lagrangian mechanics, we just lump together all generalized coordinates into a single vector $\overrightarrow{q}(t):\mathbb{R}\to {\mathbb{R}}^n$ that maps time to the full state:where each component can be anything, either the x/y/z coordinates relative to the ground of different particles, or angles, or nay other crazy thing we want.

The Lagrangian is a function ${\mathbb{R}}^n\times {\mathbb{R}}^n\times \mathbb{R}\to \mathbb{R}$ that maps:to a real number.

Then, the stationary action principle says that the actual path taken obeys the Euler-Lagrange equation:This produces a system of partial differential equations with:

The mixture of so many derivatives is a bit mind mending, so we can clarify them a bit further. At:the $q_i$ is just identifying which argument of the Lagrangian we are differentiating by: the i-th according to the order of our definition of the Lagrangian. It is not the actual function, just a mnemonic.

Then at:

However, people later noticed that the Lagrangian had some nice properties related to Lie group continuous symmetries.

Basically it seems that the easiest way to come up with new quantum field theory models is to first find the Lagrangian, and then derive the equations of motion from them.

For every continuous symmetry in the system (modelled by a Lie group), there is a corresponding conservation law: local symmetries of the Lagrangian imply conserved currents.
Genius: Richard Feynman and Modern Physics by James Gleick (1994) chapter "The Best Path" mentions that Richard Feynman didn't like the Lagrangian mechanics approach when he started university at MIT, because he felt it was too magical. The reason is that the Lagrangian approach basically starts from the principle that "nature minimizes the action across time globally". This implies that things that will happen in the future are also taken into consideration when deciding what has to happen before them! Much like the lifeguard in the lifegard problem making global decisions about the future. However, chapter "Least Action in Quantum Mechanics" comments that Feynman later notice that this was indeed necessary while developping Wheeler-Feynman absorber theory into quantum electrodynamics, because they felt that it would make more sense to consider things that way while playing with ideas such as positrons are electrons travelling back in time. This is in contrast with Hamiltonian mechanics, where the idea of time moving foward is more directly present, e.g. as in the Schrödinger equation.

Furthermore, given the symmetry, we can calculate the derived conservation law, and vice versa.

And partly due to the above observations, it was noticed that the easiest way to describe the fundamental laws of particle physics and make calculations with them is to first formulate their Lagrangian somehow: S.

TODO advantages:

Bibliography:

The function that fully describes a physical system in Lagrangian mechanics.

Per Osland, born on November 17, 1964, is a Norwegian politician affiliated with the Progress Party (Fremskrittspartiet). He has served in various political capacities, including as a Member of Parliament for Nordland from 2017 to 2021. Osland has also served as the mayor of Bø in Vesterålen and has been involved in local government and political activities at multiple levels.

Øyvind Grøn is a Norwegian mathematical physicist known for his work in the field of quantum mechanics, particularly on topics related to quantum field theory and the foundations of quantum mechanics. He has contributed to the understanding of various physical phenomena and has published papers on related subjects.

Number partitioning is a problem in combinatorial mathematics and computer science that involves dividing a set of integers into two or more subsets such that certain conditions are met. The most common form of the problem involves partitioning a set of integers into two subsets that have equal sums, known as the "Partition Problem." The Partition Problem can be formally defined as follows: Given a set of integers, can it be divided into two subsets such that the sum of the elements in each subset is equal?

BIBSYS is a Norwegian organization that provides library and information services primarily to institutions in Norway. It offers a suite of tools and systems for managing library resources, including cataloging, circulation, and digital library services. BIBSYS serves universities, colleges, and research institutions, enabling them to share resources and streamline library operations.

The Department of Petroleum Engineering and Applied Geophysics (PE) at the Norwegian University of Science and Technology (NTNU) is an academic department that focuses on education and research in the fields of petroleum engineering and geophysics. NTNU, located in Trondheim, Norway, is one of the leading technical universities in Europe and has a strong emphasis on technology and engineering disciplines.