Formal theories | Logical expressions

Theory (mathematical logic)

In mathematical logic, a theory (also called a formal theory) is a set of sentences in a formal language. In most scenarios, a deductive system is first understood from context, after which an element of a deductively closed theory is then called a theorem of the theory. In many deductive systems there is usually a subset that is called "the set of axioms" of the theory , in which case the deductive system is also called an "axiomatic system". By definition, every axiom is automatically a theorem. A first-order theory is a set of first-order sentences (theorems) recursively obtained by the inference rules of the system applied to the set of axioms. (Wikipedia).

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Logic: The Structure of Reason

As a tool for characterizing rational thought, logic cuts across many philosophical disciplines and lies at the core of mathematics and computer science. Drawing on Aristotle’s Organon, Russell’s Principia Mathematica, and other central works, this program tracks the evolution of logic, be

From playlist Logic & Philosophy of Mathematics

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Logic - Types of Statements

An introduction to the general types of logic statements

From playlist Geometry

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Teach Astronomy - Logic

http://www.teachastronomy.com/ Logic is a fundamental tool of the scientific method. In logic we can combine statements that are made in words or in mathematical symbols to produce concrete and predictable results. Logic is one of the ways that science moves forward. The first ideas of

From playlist 01. Fundamentals of Science and Astronomy

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Number theory Full Course [A to Z]

Number theory (or arithmetic or higher arithmetic in older usage) is a branch of pure #mathematics devoted primarily to the study of the integers and integer-valued functions. Number theorists study prime numbers as well as the properties of objects made out of integers (for example, ratio

From playlist Number Theory

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The History of Logic: The Logic of Aristotle

A few clips of Gabriele Giannantoni explaining Aristotelian logic, the logic of Aristotle. These clips come from the Multimedia Encyclopedia of the Philosophical Sciences. More Short Videos: https://www.youtube.com/playlist?list=PLhP9EhPApKE8v8UVlc7JuuNHwvhkaOvzc Aristotle's Logic: https:

From playlist Logic & Philosophy of Mathematics

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The problem with `functions' | Arithmetic and Geometry Math Foundations 42a

[First of two parts] Here we address a core logical problem with modern mathematics--the usual definition of a `function' does not contain precise enough bounds on the nature of the rules or procedures (or computer programs) allowed. Here we discuss the difficulty in the context of funct

From playlist Math Foundations

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The Scientific Method and the question of "Infinite Sets" | Sociology and Pure Maths| N J Wildberger

Let's get some kind of serious discussion going about the differences in methodology and philosophy between the sciences and mathematics, and how these differences manifest themselves in the attitude towards the logical foundations of mathematics. In particular we look at a bulwark notio

From playlist Sociology and Pure Mathematics

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Philosophy of Mathematics & Frege (Dummett 1994)

Michael Dummett gives a talk on Frege and the philosophy of mathematics. For a good introduction to the philosophy of mathematics, check out: https://www.youtube.com/watch?v=UhX1ouUjDHE Another good introduction to the philosophy of mathematics: https://www.youtube.com/watch?v=XyXWnGFKTkg

From playlist Logic & Philosophy of Mathematics

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Gödel's Incompleteness Theorems: An Informal Introduction to Formal Logic #SoME2

My entry into SoME2. Also, my first ever video. I hope you enjoy. The Book List: Logic by Paul Tomassi A very good first textbook. Quite slow at first and its treatment of first-order logic leaves a little to be desired in my opinion, but very good on context, i.e. why formal logic is im

From playlist Summer of Math Exposition 2 videos

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Michio Kaku - Why the ‘Unreasonable Effectiveness’ of Mathematics?

Free access to Closer to Truth's library of 5,000 videos: http://bit.ly/376lkKN What is it about mathematics that it can describe so accurately the world around us? From quantum physics, the very smallest features and forces of the foundations of matter and energy, to cosmology, the very

From playlist Why the ‘Unreasonable Effectiveness’ of Mathematics? - CTT Interview Series

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Lecture 1: Invitation to topos theory

This talk introduces the motivating question for this semester of the Curry-Howard seminar, which is how to organise mathematical knowledge using topoi. The approach sketched out in the talk is via first-order theories, their associated classifying topoi, and adjoint pairs of functors betw

From playlist Topos theory seminar

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Frege, Russell, & Modern Logic - A. J. Ayer & Bryan Magee (1987)

In this program, A. J. Ayer discusses the work of Gottlob Frege, Bertrand Russell, and modern logic with Bryan Magee. This is from the 1987 series on great philosophers. #Philosophy #Bryanmagee #BertrandRussell

From playlist Bryan Magee Interviews - The Great Philosophers (1987)

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SHM - 16/01/15 - Constructivismes en mathématiques - Thierry Coquand

Thierry Coquand (Université de Gothenburg), « Théorie des types et mathématiques constructives »

From playlist Les constructivismes mathématiques - Séminaire d'Histoire des Mathématiques

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Intro to the Philosophy of Mathematics (Ray Monk)

A good introduction to the philosophy of mathematics by Ray Monk. He considers the issue of the nature of mathematical truth - what mathematics is actually about - and discusses the views of Plato, Aristotle, Kant, Frege and Russell. What is mathematics about? Is mathematics something disc

From playlist Logic & Philosophy of Mathematics

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Univalent Foundations Seminar - Steve Awodey

Steve Awodey Carnegie Mellon University; Member, School of Mathematics November 19, 2012 For more videos, visit http://video.ias.edu

From playlist Mathematics

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Quantum Mechanics -- a Primer for Mathematicians

Juerg Frohlich ETH Zurich; Member, School of Mathematics, IAS December 3, 2012 A general algebraic formalism for the mathematical modeling of physical systems is sketched. This formalism is sufficiently general to encompass classical and quantum-mechanical models. It is then explained in w

From playlist Mathematics

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Inference: A Logical-Philosophical Perspective - Moderated Conversation w/ A.C. Paseau and Gila Sher

Inference:  A Logical-Philosophical Perspective. Moderated Conversation with Gila Sher, Department of Philosophy, University of California, San Diego on the talk by Alexander Paseau, Faculty of Philosophy, University of Oxford. The Franke Program in Science and the Humanities Understandi

From playlist Franke Program in Science and the Humanities

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Resolution (logic) | Natural deduction | Theorem | Principle of explosion | Löwenheim–Skolem theorem | Logical consequence | Interpretability | Decidability of first-order theories of the real numbers | Well-formed formula | Formal language | Compactness theorem | Sequent calculus | Decidability (logic) | Lindenbaum's lemma | Method of analytic tableaux | Sentence (mathematical logic) | True arithmetic | Second-order logic | Axiomatic system | Formal proof | Deduction theorem | Mathematical theory | List of first-order theories | Signature (logic) | Complete theory | Axiom | Structure (mathematical logic) | Mathematical logic | Ω-consistent theory | Gödel's completeness theorem | Formal system | Rule of inference | Satisfiability | First-order logic | Recursion