Practice exercises.
Anyone young is lucky. Ax(Yx
-> Lx)
No one unhappy is lucky. Ax(~Hx
-> Lx)
All young people are happy and lucky. Ax(Yx
-> (Hx & Lx))
If someone is young then she is lucky.
Ax(Yx -> Lx)
If there is someone young then everyone is lucky.
Ex(Yx) -> Ax(Lx)
There are those who are rich but not happy.
Ex(Rx & ~Hx)
Anyone rich but unhappy is unlucky. Ax((Rx
& ~Hx) -> ~Lx)
Only the young are lucky. Ax(Lx
-> Yx)
If only the rich are lucky then everyone is unhappy.
Ax(Lx -> Rx) -> Ax(~Hx)
The young are lucky only if they are happy.
Ax(Yx -> (Lx -> Hx)) or
Ax ((Yx & Lx) -> Hx)