# Tag Info

Accepted

### Standard reference for basic model theory definitions

Here is one possibility, but other people might use different words. I will use first-order logic as a running example. Language The language is a collection of expressions, which are syntactic ...
• 27.5k
Accepted

### Are there two definitions of Cobham's thesis?

Cobham's thesis is essentially the Extended Church-Turing thesis. Historians of computer science have gone back and figured out who first proposed it, and attached his name to it. What Cobham was ...
• 23.9k
Accepted

### Why is differential privacy defined over the exponential function?

This answer may be disappointing, but working on a log scale really mostly just makes the formulas nicer. The definition, as written, has the following important properties: Composition: If $A(\cdot)$...
• 18.1k
Accepted

### On the notion of positive rank of a matrix

There are examples of $n\times n$ real matrices of rank at most $3$ and non-negative rank at least $\sqrt{2n}$. So the non-negative rank cannot be bounded by any function of the rank in general. The ...
• 18.1k

### Definition of near-linear algorithm

A natural definition of "near-linear" should be: A function $f:\mathbb{N}\to\mathbb{N}$ is near-linear, if $~f(n)\in O(n^{1+\varepsilon})~$ for all $\varepsilon>0$.
• 5,742
Accepted

### Precise definition of syntatic categories / syntatic domains in abstract syntax

Most people avoid giving precise descriptions of what a syntactic category is, because if you do it properly with all the details, the ratio of insight to necessary mathematical sophistication ends up ...
• 32.1k

### The theory of definitions in first order logic

I don't have the books handy at the moment, but I think Shoenfield's "Mathematical Logic" and Hinman's "Fundamentals of Mathemtical Logic" would contain much if not all of what you're looking for. ...

### Kolmogorov Complexity of a Decidable Language

Yes, depending on what kinds of inputs you consider (see below). $KC(x) =^* KCDL(L_x)$, where $L_x$ is the language which consists only of the string $x$, and $=^*$ means equals up to an additive ...
• 36.3k