williamstein/ent — pull request #1 by dospromptman (2013-06-25 12:28:49+00:00)
Title: Minor edit to remove redundant word in Preface

The sentence "The reader should know how to read and write mathematical proofs and must have know the basics of groups, rings, and fields" seems to have a redundant word.

I have removed the word "have" so the sentence becomes "The reader should know how to read and write mathematical proofs and must know the basics of groups, rings, and fields"