/explore

Click through on any links that interest you or select the planets on the right to continue exploring the Outer Web.
You are here

www.umsu.de
| | jdh.hamkins.org

Philosophy of Mathematics, Exam Paper 122, Oxford University Wednesdays 12-1 during term, Radcliffe Humanities Lecture Room Joel David Hamkins, Professor of Logic Lucy, Charles - Personifications o...
4.8 parsecs

Travel
| |
| | xorshammer.com

Let $latex \mathrm{PA}$ be Peano Arithmetic. Gödel's Second Incompleteness Theorem says that no consistent theory $latex T$ extending $latex \mathrm{PA}$ can prove its own consistency. (I'll write $latex \mathrm{Con}(T)$ for the statement asserting $latex T$'s consistency; more on this later.) In particular, $latex \mathrm{PA} + \mathrm{Con}(\mathrm{PA})$ is stronger than $latex \mathrm{PA}$. But certainly, given that...
5.9 parsecs

Travel
| |
| | blog.sigfpe.com

[AI summary] The article explains why defining a truth predicate for set theory (ZF) is impossible despite the success of similar definitions in propositional calculus and Peano arithmetic, based on Tarski's theorem and the limitations of transfinite recursion when applied to infinite collections of children.
5.3 parsecs

Travel
| |
| | mathematicaloddsandends.wordpress.com

The function $latex f(x) = x \log x$ occurs in various places across math/statistics/machine learning (e.g. in the definition of entropy), and I thought I'd put a list of properties of the function here that I've found useful. Here is a plot of the function: $latex f$ is defined on $latex (0, \infty)$. The only...
29.5 parsecs

Travel
|