6.2ex IV Symbolizations

Symbolize as before. Only now you may use quantifiers and variables, names and predicates.

  • You may use the old keyboard shortcuts except that now you must type upper case letters for the predicates. (You can see why, right?)
  • Use the '^' for the upside down-A and the '%' for the backward-E. (It's really worth it to download and install the Logic font! See the home page.)
  • You may type a quantifier and variable without parentheses. They will be added for you! E.g., just type '^x' and this will be interpreted as '(^x)'.
  • As the exercises get longer, it will take the Café longer to figure out whether or not your answer is correct. Progress is indicated on the status bar.


More Directions, Hints, and Shortcuts...

















universe of discourse: people in a symbolic logic class
j: John (a student in the universe of discourse)
Lx: x is late for class
Kxy: x knows y.

  1. Someone is late.
  2. Everyone is late.
  3. John knows everyone in class.
  4. Everyone knows John.
  5. John knows someone in class.
  6. Everyone is late but not everyone knows John.
  7. No one is late.
  8. No one knows John.
  9. There is a tardy student who knows John.
  10. Each student is late.
  11. John knows a student.
  12. Not everyone knows John.