Are there minimum criteria for a programming language being Turing complete?

Question Detail: 

Does there exist a set of programming language constructs in a programming language in order for it to be considered Turing Complete?

From what I can tell from wikipedia, the language needs to support recursion, or, seemingly, must be able to run without halting. Is this all there is to it?

Asked By : Khanzor

Best Answer from StackOverflow

Question Source : http://cs.stackexchange.com/questions/991

Answered By : Raphael

I always though that $\mu$-recursive functions nailed it. Here is what defines the whole set of computable functions; it is the smallest set of functions containing resp. closed against:

1. The constant $0$ function
2. The successor function
3. Selecting parameters
4. Function composition
5. Primitive Recursion
6. The $\mu$-operator (look for the smallest $x$ such that...)

Check above link for details; you see that it makes for a very compact programming language. It is also horrible to program in -- no free lunch. If you drop any of those, you will lose full power, so it is a minimal set of axioms.

You can translate those quite literally into basic syntactical elements for WHILE programs, namely

1. The constant 0
2. Incrementation _ + 1
3. Variable access x
4. Program/statement concatenation _; _
5. Countdown loops for ( x to 0 ) do _ end
6. While loops while ( x != 0 ) do _ end