New to python

[oxymoron]

Working on some python scrips with a friend. Got these exercisees;

ia1 = Interpretation([knows(bob,john),knows(john,bob),knows(mary,alice),knows(alice,mary)],[bob,john,mary,alice])
 

This is supposed to be symmetric... but this is as far as I get.

f1a1 = forall(x, knows(x, bob)) > forall(y, knows(bob, y)) & forall(x, knows(x, mary)) > forall(y, knows(mary, y))
 
print 'This Is symmetric:', f1a1.val(ia1)

I shouldnt use the name bob, mary and so on, but if I use the variables a,b, for example I get the error that its not defined.

ia2 = Interpretation([knows(bob,john),knows(john,bob),knows(mary,alice),knows(alice,mary)],[bob,john,mary,alice])
 

this part is supposed to be transitive. From what I can se (though Im kind of tired) it is not transitive. But I just cant seem to find the right answser.

f1a2 = forall(z, forall(y, forall(x, (knows(x, y) & forall(x, knows(y,z)) > forall(x, knows(x, z))))))
print 'This Is Transitive:', f1a2.val(ia2)

and finally this, its going to be symmetric.

ia5 = 
Interpretation([loves(bob,mary),loves(john,john),loves(mary,alice),loves(bob,alice)],[bob,john,mary,alice])
 

and this is how far I came on this one

f1a5 = forall(x, forall(y, forall(z, loves(x, y) & loves(y, z) > loves(x, z))))
print 'This is symmetric', f1a5.val(ia4)
 

cant find whats wrong with this one.

Would really appreciate any help on these exercises.

// Sweden