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Thu 20 May, 2010 09:21 am

Could anyone please explain to me how functions work in predicate logic. I am not sure I understand them correctly.

I have several problems involving them

1) U.D. People

Tx: x is friendly

Lxy: x admires y

f(x): x's father

And 'No one who is friendly is admired by his/her father'

I got

NOT (]x)(]y)(Lxy & Tf(y))

But that doesn't look right at all

Another one 2)

U.D: People

Tx: x is nice

Lxy: x hits y

f(x): x's sister

And to symbolise - Someone who hits his sister isn't nice

I got

(Vx)(Lxf(x)> NOT Tx)

This isn't for homework but I have a test in a few days and I've been going over some excercises but can't find the answers anywhere. Would really appreciate it if someone could tell me if I am doing this right