Logical Venn Diagrams

What you will be able to do

• Classify each pair of terms as separate, one-inside-the-other, or overlapping.
• Pick the single diagram that satisfies every pairwise relation at once.
• Read a region-count diagram to find 'only X', 'X and Y', and 'at least one'.
• Avoid the trap of forcing an overlap that real-world meaning rules out.

What is inside this lesson

1. 1Two forms of the question
2. 2Three ways two classes can relate
3. 3Choosing the diagram
4. 4Reading a region-count diagram
5. 5Worked examples
6. 6Common mistakes
7. 7Quick revision
8. 8Practice