# Copyright

Jenna Woodrow

Unless otherwise noted, *Elementary Formal Logic* (formally *A Concise Introduction to Logic*) is (c) 2017 by Craig DeLancey. The textbook content was initially produced by Craig DeLancey and is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except for the following content changes and additions, which are (c) 2019 by Jenna Woodrow, and are licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Several symbols have been updated throughout the text, and content has been added to supplement the original content. Extra interactive exercises have been added to each chapter as additional learning tools, along with downloadable documents for the offline full exercise question sets.

The following changes have been made across the textbook:

- Conjunction symbol ‘^’ changed to ‘&’
- Negation symbol ‘¬’ changed to ‘~’
- Line numbers for proofs moved to the far left of the diagram
- Truth table formatting changed so that each part of a sentence has its own column (in some instances the tables were left as original to convey a point)

The following changes and additions have been made to these chapters:

**Chapter 1**

- 1.5 Logical connectives section added
- 1.6 Key Concepts section added
- 1.7 Exercises section added
- Original Problems section excluded

**Chapter 2**

- distributing truth values section added to 2.1
- 2.7 How to Make a Truth Table section added
- link to 2.7 added at the end of 2.1
- Reversed symbolization in 2.6 Alternative symbolizations for negation to match the global symbolization change mentioned above
- 2.8 Key Concepts section added
- 2.9 Exercises section added
- Original Problems section has been moved to the Additional Problems section of the 2.9 Exercises section

**Chapter 3**

- 3.7 Key Concepts section added
- 3.8 Exercises section added
- Original Problems section has been moved to the Additional Problems section of the 3.8 Exercises section

**Chapter 4**

- 4.5 How to Make a Direct Proof section added
- 4.6 Key Concepts section added
- 4.7 Exercises section added
- Original Problems section has been moved to the Additional Problems section of the 4.7 Exercises section

**Chapter 5**

- 5.6 Complex sentences content added, changed, and removed
- 5.7 Key Concepts section added
- 5.8 Exercises section added
- Original Problems section has been moved to the Additional Problems section of the 5.8 Exercises section

**Chapter 6**

- 6.2 Conditional derivation content added, changed, and removed
- 6.5 How to Make a Conditional Proof section added
- 6.6 Key Concepts section added
- 6.7 Exercises section added

**Chapter 7**

- 7.4 Reasoning with disjunctions section had content added
- 7.6 Key Concepts section added
- 7.7 Exercises section added (note that the original problems were included and adapted in this section)

**Chapter 8**

- 8.4 How to Make an Indirect Proof section added
- 8.5 Key Concepts section added
- 8.6 Exercises section added (note that some original problems were included and adapted in this section, while others were removed from the text completely)

**Chapter 9**

- 9.7 Using theorems section content added, changed, and removed
- 9.8 How to Make a Biconditional Proof and How to Prove a Theorem section added
- 9.9 Key Concepts section added
- 9.10 Exercises section added (note that some original problems were adapted, some were drawn from other sections, and some were removed from the text completely)

**Chapter 10**

- 10.1 Elements of the language section – added a translation key
- 10.2 Reasoning with the language – modified ‘Rules of Inference’ table, changed some content, adapted proof schemas, added ‘Rules of Replacement’ and ‘Common and useful theorems’ tables

You are free to use or modify (adapt) any of this material providing the terms of the Creative Commons licenses are adhered to.