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 1306

forcing, large cardinals, descriptive set theory, infinite combinatorics, cardinal characteristics, forcing axioms, ultrapowers, measures, reflection, pcf theory, models of set theory, axioms of set theory, independence, axiom of choice, continuum hypothesis, determinacy, Borel equivalence relations, Boolean-valued models, embeddings, orders, relations, transfinite recursion, set theory as a foundation of mathematics, the philosophy of set theory.

35 votes

Injectivity implies surjectivity

There is an improvement of the answer of Joseph Van Name which I feel is much more in the spirit in the question asked: Let $(X,d)$ be a compact metric space, and assume that the mapping $f\colon X\t …
43 votes
Accepted

Is there a natural bijection from $\mathbb{N}$ to $\mathbb{Q}$?

There is a following result which is quite lovely, I think (I don't remember right away whose result this is): Let us define a function $f\colon\mathbb{N}\to\mathbb{Q}^+$ as follows: $f(1)=1$, and al …
Vladimir Dotsenko's user avatar
3 votes

Non-Formal Applications: Higman and Kruskal

Unsurprisingly, there are various ways in which Higman's lemma is used in the context of Gröbner bases. One interesting recent example : http://www.msri.org/people/members/chillar/files/HS-MonoidGBFin …