16. All ${\displaystyle y}$ are ${\displaystyle x}$. i.e.

1

0

17. No ${\displaystyle y}$ exist. i.e.

0

0

18. Some ${\displaystyle y}$ are ${\displaystyle x^{\prime }}$. i.e.

1

15. Some ${\displaystyle y}$ exist. i.e.

1

1. No ${\displaystyle x}$ are ${\displaystyle y^{\prime }}$.

2. No ${\displaystyle x}$ exist.

3. Some ${\displaystyle x}$ exist.

4. All ${\displaystyle x}$ are ${\displaystyle y^{\prime }}$.

5. Some ${\displaystyle x}$ are ${\displaystyle y}$. i. e. Some good riddles are hard.

6. All ${\displaystyle x}$ are ${\displaystyle y}$. i. e. All good riddles are hard.

7. No ${\displaystyle x}$ exist. i. e. No riddles are good.

[See pp. 41, 2]