Define a set X of strings in the symbols 0 and 1 as follows. B. 0 and 1 are in X. R1₁. If x and y are in X, so is xxyy. R₂. If x and y are in X, so is xyx. Explain why the string 01001011 EX using the definition. Build up the string step by step, and justify each step by referring to the appropriate part of the definition. 0 is in X B. B. 1 is in X R2. If 0 and 1 are in X, so is 0 0 R1. If 010 and 1 are in X, so is

Define a set X of strings in the symbols 0 and 1 as follows. B. 0 and 1 are in X. R1₁. If x and y are in X, so is xxyy. R₂. If x and y are in X, so is xyx. Explain why the string 01001011 EX using the definition. Build up the string step by step, and justify each step by referring to the appropriate part of the definition. 0 is in X B. B. 1 is in X R2. If 0 and 1 are in X, so is 0 0 R1. If 010 and 1 are in X, so is

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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Write a regular expression for the set of strings over the alphabet {a, b} that have at least one a andat least one b. For example, aaaba and bbaba are strings in the set, but aaaa and bbb are not.
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