lkuper

<lkuper> is it equivalent to say that a function is invertible and that it's a bijection?
<shachaf> Yes.
<lkuper> ok :)
<shachaf> But you have to be careful if you have "functions" between more complicated structures.
<shachaf> In which case there might be more requirements on the inverse. But not with plain old functions.
<lkuper> ah. by ""functions" between more complicated structures", do you mean, like, some other kind of morphism?
<lkuper> (I'm dealing with plain old functions here, but curious)
<shachaf> Right.
<shachaf> E.g. you might care that the inverse of a continuous function is continuous, or something.
<lkuper> I see.  so, maybe another way to say this is that, when dealing with sets, it turns out bijectivity and invertibility coincide, but invertibility is a more general concept and applies to fancier kinds of objects too

lkuper

### Keybase proof

I hereby claim:

  * I am lkuper on github.
  * I am lindsey (https://keybase.io/lindsey) on keybase.
  * I have a public key whose fingerprint is 6832 D0DB 85DB 2D9A 10DC  B4B9 DF53 470B 4C78 460C

To claim this, I am signing this object:

lkuper

    #[lang="strdup_uniq"]
    #[cfg(not(test))]
    #[allow(missing_doc)]
    #[inline]
    pub unsafe fn strdup_uniq(ptr: *u8, len: uint) -> ~str {
        from_buf_len(ptr, len)
    }

lkuper

%====Set up Listings===============================================================

\definecolor{darkgreen}{rgb}{0,0.5,0}
\definecolor{darkred}{rgb}{0.5,0,0}
\lstloadlanguages{Haskell}
\lstnewenvironment{code}
    { % \centering
      \lstset{}%
      \csname lst@SetFirstLabel\endcsname}
    { %\centering

lkuper

nbrs :: G.Graph -> G.Vertex -> [G.Vertex]
nbrs g v =
  map snd edgesFromNode where
    edgesFromNode = filter (\(v1, _) -> v1 == v) (G.edges g)

lkuper

import threading

class LVar(object):
    def __init__(self):
        self.value = 0

    def get(self, threshold):
        while not self.value >= threshold:
            pass
        return

lkuper

(load "mkprelude.scm")

(define peanoo
  (lambda (n out)
    (conde
      [(== n (build-num 0)) (== '(O) out)]
      [(fresh (n1 res)
         (-o n (build-num 1) n1)
         (conso 'S res out)
         (peanoo n1 res))])))

lkuper

trait Printable {
    fn print(&self) { println!("{:?}", *self) }
}

impl Printable for int {}

impl Printable for ~str {
    fn print(&self) { println(*self) }
}

lkuper

landin:lvar-examples lkuper$ git reset f550a2
Unstaged changes after reset:
M	README.md
M	parallel-and.hs
M	repeated-write-lvar-max-counter.hs
landin:lvar-examples lkuper$ git st
# On branch master
# Your branch is behind 'origin/master' by 8 commits, and can be fast-forwarded.
#   (use "git pull" to update your local branch)
#

lkuper

landin:haskell lkuper$ ./install_lots.sh --enable-tests
./install_lots.sh: line 22: [: missing `]'
+ OPTS=' -fnewgeneric -fgeneric'
+ '[' -e .cabal-sandbox ']'
+ cabal install -fnewgeneric -fgeneric ./lvish ./par-classes/ ./par-transformers/ ./par-collections/ --enable-tests
Resolving dependencies...
In order, the following will be installed:
par-classes-1.0.1 (reinstall)
par-collections-1.0 *test (reinstall) changes: HUnit-1.2.5.2 added,
atomic-primops-0.4 added, monad-par-0.3.4.6 added, test-framework-0.8 added,