Classes of recursive functions based on Ackermann’s function

study of hash functions based on chaotic maps

توابع درهم نقش بسیار مهم در سیستم های رمزنگاری و پروتکل های امنیتی دارند. در سیستم های رمزنگاری برای دستیابی به احراز درستی و اصالت داده دو روش مورد استفاده قرار می گیرند که عبارتند از توابع رمزنگاری کلیددار و توابع درهم ساز. توابع درهم ساز، توابعی هستند که هر متن با طول دلخواه را به دنباله ای با طول ثابت تبدیل می کنند. از جمله پرکاربردترین و معروف ترین توابع درهم می توان توابع درهم ساز md4, md...

On Uniform Learning of Classes of Recursive Functions

A classical learning problem in inductive inference consists of identifying each function of a given class of recursive functions from a finite number of its output values. Uniform learning is concerned with the design of single programs solving infinitely many classical learning problems. For that purpose the program reads a description of an identification problem and is supposed to construct...

A Note on Recursively Enumerable Classes of Partial Recursive Functions

A class F of partial recursive functions is called recursively enumerable if there exists an r.e. set J ⊆ N such that F = {φi | i ∈ J}. We prove that every r.e. class F of partial recursive functions with infinite domains must have a recursive witness array, i.e. there is a computable array of finite sets X = [Xn]n∈ω such that (i) for every f ∈ F one has f(n) ∈ Xn for infinitely many n and (ii)...

Real Recursive Functions and Baire Classes

Recursive functions over the reals [6] have been considered, first as a model of analog computation, and second to obtain analog characterizations of classical computational complexity classes [2]. However, one of the operators introduced in the seminal paper by Cris Moore (in 1996), the minimalization operator, creates some difficulties: (a) although differential recursion (the analog counterp...

Classes of sub-recursive function Selected bibliography