NONCOMPUTABLE FUNCTIONS IN THE BLUM-SHUB-SMALE MODEL

作者：Calvert Wesley^*; Kramer Ken; Miller Russell

来源：Logical Methods in Computer Science, 2011, 7(2): 15.

DOI：10.2168/LMCS-7(2:15)2011

• algebraic real numbers
• Blum-Shub-Smale computation
• BSS machine
• oracle computation
• relative computability

Working in the Blum-Shub-Smale model of computation on the real numbers, we answer several questions of Meer and Ziegler. First, we show that, for each natural number d, an oracle for the set of algebraic real numbers of degree at most d is insufficient to allow an oracle BSS-machine to decide membership in the set of algebraic numbers of degree d + 1. We add a number of further results on relative computability of these sets and their unions. Then we show that the halting problem for BSS-computation is not decidable below any countable oracle set, and give a more specific condition, related to the cardinalities of the sets, necessary for relative BSS-computability. Most of our results involve the technique of using as input a tuple of real numbers which is algebraically independent over both the parameters and the oracle of the machine.

• 出版日期2011