Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options not deleted user 6153

first-order and higher-order logic, model theory, set theory, proof theory, computability theory, formal languages, definability, interplay of syntax and semantics, constructive logic, intuitionism, philosophical logic, modal logic, completeness, Gödel incompleteness, decidability, undecidability, theories of truth, truth revision, consistency.

8 votes
2 answers
572 views

Proof theory and primitive roots

I have had this question on my mind for two decades. We know, after Heath-Brown, that one out (say) of 3, 5, 7 is a primitive root mod p for infinitely many primes p. We just don't know which one. (We …
9 votes

What is the geometry of an undecidable diophantine equation?

You have a typical recursively enumerable set S of integers, and a set X of lattice points cut out by a multivariate polynomial. We are talking about S being the projection (onto one axis) of X. Given …
Charles Matthews's user avatar
0 votes

Did Pogorzelski claim to have a proof of Goldbach's Conjecture?

The "why not" is about the onus of proof. The word "false" does not properly qualify a proof, but a proposition. The procedure by which proofs become accepted as essentially correct is by publication …
Charles Matthews's user avatar
3 votes

Infinite games: are they well defined?

I'm aware of quite a number of theories of "games" in mathematics. A not-overly-naive preliminary is to ask about what these are, and then what they have in common. I think the earliest is probably …
Charles Matthews's user avatar
4 votes

Stone Spaces, Locales, and Topoi for the (relative) beginner

The texts by Vickers and Johnstone are rather different, and certainly are different in intention. I was struck by a remark made to me by a leading computer scientist, to the effect that Stone Spaces …
Charles Matthews's user avatar
5 votes

Connections between ultrafilters in topology and logic

My feeling, which may be ignorant, is that these intuitions go all the way back to Leibniz. There "point" was in some way ridded of a silly definition like "position but no magnitude", and was replace …
Charles Matthews's user avatar
15 votes

Au revoir, law of excluded middle?

I don't know whether this will be helpful, but here goes. There used to be things called the "Laws of Thought", and they used to be equated (tendentiously) with sort-of axioms for rationality, when "a …
Charles Matthews's user avatar