# Physics Welcome to the physics page. Some special physical environments that will be used in this section are listed and explained below. * *Axioms*: fundamental assumptions or self-evident truths that serve as the basis for physical reasoning within a particular system. Axioms are not proved within the system but are taken as starting points from which other physical statements are deduced. * *Postulates*: a statement that is accepted without proof, typically serving as starting assumptions in a specific physical theory or system. Postulates are similar to axioms but are often specific to a particular branch in physics. * *Principles*: a fundamental rule or concept that govern physical reasoning. Principles may be derived from axioms, postulates, or empirical observations and are used to guide mathematical analysis or argumentation. * *Definitions* : a precise and unambiguous description of the meaning of a physical term. It characterizes the meaning of a word by giving all the properties and only those properties that must be true. * *Theorems* : a mathematical statement that is proved to be true using rigorous mathematical reasoning. In a mathematical text, the term theorem is often reserved for the most important results. * *Propositions* : an often interesting result, but generally less important than a theorem. * *Lemmas* : a minor result whose purpose is to help in proving a theorem. It is a stepping stone on the path to proving a theorem. * *Corollaries* : a result in which the proof relies heavily on a given theorem. * *Proofs* : a convincing argument that a certain mathematical statement is necessarily true. A proof generally uses deductive reasoning and logic but also contains some amount of ordinary language. The physics sections of this wiki are based on various books and lectures. A comprehensive list of references can be found below. * The sections of signal and vector analysis in mathematical physics are based on the lectures and lecture notes of Jan van Dijk. * The section of optics in electromagnetism is based on the lectures of Jürgen Kohlhepp and the book Principles of Physical Optics by Chuck Bennet.