Take the 2-minute tour ×
MathOverflow is a question and answer site for professional mathematicians. It's 100% free, no registration required.

How can I solve the following problem:

$f, \pi, g$ accept one, two and three arguments respectively. If you know that $f, \pi, g$ are primitive recursive functions prove that $h$ defined as:

$\begin{array}{lcl} h(0, y) \simeq f(y) \newline h(x + 1, y) \simeq g(x, y, h(x, \pi(x, y))) \end{array}$ is also primitive recursive function.

share|improve this question
6  
This seems oddly like homework. –  Igor Rivin Nov 23 '11 at 21:25
    
I voted to re-open, since the critical comments and answers below seem to have overlooked the function $\pi$. A direct instance of primtive recursion would provide $h(x+1,y)$ in terms of $x,y$ and $h(x,y)$, rather than $h(x,\pi(x,y))$ as here. –  Joel David Hamkins Nov 24 '11 at 1:14
2  
Joel is right to point out that this is not just the definition of primitive recursion. Nevertheless, it still looks like homework to me. –  Andreas Blass Nov 24 '11 at 1:29
    
What resources do you allow yourself? I could mention hints and sources, but if that would "cheapen the grade", I'd rather not say anything. Gerhard "Ask Me About System Design", 2011.11.23 –  Gerhard Paseman Nov 24 '11 at 2:04
add comment

closed as too localized by Igor Rivin, Henry Cohn, Todd Trimble, Andrej Bauer, Yemon Choi Nov 23 '11 at 23:47

This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

Browse other questions tagged or ask your own question.