Metamath is a computer language and an associated computer program for archiving, verifying, and studying mathematical proofs. The Metamath language is simple and robust, with an almost total absence of hard-wired syntax, and we believe that it provides about the simplest possible framework that allows essentially all of mathematics to be expressed with absolute rigor. While simple, it is also powerful; the Metamath Proof Explorer (MPE) database has over 23,000 proven theorems and is one of the top systems in the "Formalizing 100 Theorems" challenge. This book explains the Metamath language and program, with specific emphasis on the fundamentals of the MPE database.

Preach great sermons and plan innovative worship services with the newest edition of "Nelson's Annual Preacher's Sourcebook. ""Nelson's Annual Preacher's Sourcebook, Volume 1 "is the same sermon planner you have come to depend on for over ten years with a new topical focus. Outstanding pastors provide an entire year's worth of preaching and worship resources for every Sunday. With an emphasis on the family, sermon series on the names of God, and special sermons for holidays, preachers can a plan a full year of services! Look for a new volume every fall.

Features include:

• Sermons, creative outlines, illustrations, and quotes for every Sunday of the year
• Worship helps, including hymns, prayers, and Scripture texts
• Inspirational thoughts and preaching techniques
• Sermons for special occasions and holidays