Prove that upside-down regular expressions without complement operation cannot describe all regular languages. **You can prove this by finding a regular language and showing that an upside-down RE cannot describe it. You can pick a finite language, then show that if there is an upside-down RE that describes it then the language must contain some extra elements. For the last part, you can make a proof by induction over the RE.

Prove that upside-down regular expressions without complement operation cannot describe all regular languages. **You can prove this by finding a regular language and showing that an upside-down RE cannot describe it. You can pick a finite language, then show that if there is an upside-down RE that describes it then the language must contain some extra elements. For the last part, you can make a proof by induction over the RE.

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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