Errata in chapters (class notes)
--------------------------------


chapter 6

section 6.4

In all the examples, sometimes zero and sometimes empty circle is used, but this is a typo, they should all be the empty circle.

p.8
Example of variable assignment, should use ^v rather than ^i (e.g. x^i=emptycircle).

In the example for value assignment, f(a)^{iv} should be empty circle and not full circle, and f(z)^{iv} should be full circle 
and not empty circle. 

Error in example: r(b,z)^{iv} also comes out true. But e.g. r(b,y)^{iv} comes out false.

Head of p.10, last sentence of section 6.4 - should use the same "v" in "free variable v" and "a model of Av.phi".

p. 13, question 2:
Need to add "likes(x,y) means that x likes y".


chapter 7

In all the examples, sometimes zero and sometimes empty circle is used, but this is a typo, they should all be the empty circle.

p.9
"(3) each function constant denotes a function that maps ground terms to themselves."  - this is incorrect. Need 
something like: "each function constant f denotes a function that maps each ground term tau to the term f(tau)"


chapter 9

On the example on page 8, on the Existentials out step, the Skolem function we use has a fn constant g that already 
existed in our database, but it should be a new symbol.