IIm10/BuK-Übung02 G2

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<language>Scheme</language>
== Intuitiver Berechnbarkeitsbegriff ==
<code id="4d89f4861d3aa">
(define haelt-fuer-n?
  (λ (f n)
    (if (integer? (f n))
        #t
        #f)))
</code>

<code id="4d89f4861d42c">
(define haelt?
  (λ (f)
    (haelt-fuer-n? f 0)))
</code>

<code id="4d89f4861d48a">
(define crazy
  (λ (n)
    (if (haelt? crazy n)
        (crazy n)
        n)))
</code>

<code id="4d89f4861d4e8">
(define haelt-tricky?
  (λ (f timeout)
    (letrec 
        ([ft (thread f)]
         [helper
          (λ (timeLeft)
            (if (thread-running? ft)
                (if (= timeLeft 0)
                    #f
                    (begin (sleep 1) (helper (- timeLeft 1))))
                #t))])
      (helper timeout))))
</code>

<code id="4d89f4861d54c">
(define test1
  (λ ()
    (print "hallo")))

(define test2
  (λ ()
    (test2)))
</code>

<run id="4d89f4861d5c2">
(haelt-tricky? test1 10)
</run>

<run id="4d89f4861d616">
(haelt-tricky? test2 10)
</run>

=== Bijektive Funktion ===
Es sei eine Funktion <math>f:{\mathbb{N}}^{+}  \rightarrow {\mathbb{Q}}^{+}</math> gegeben: <br><br>
<math>
f(n) = \left\{\begin{matrix}
1, & \mbox{wenn } n=1 \mbox{,}\\ 
f(\frac{n}{2})+1, & \mbox{wenn } n \mbox{ gerade,}\\ 
\frac{1}{f(n-1)}, & \mbox{wenn } n \mbox{ ungerade.}
\end{matrix}\right.
</math>