Suggestion for General rules given on page 225 And other error in Chapter 7
I purchased the book recently and think I have the 2nd Printing, so
these errors should be in all books. Please do correct me in case I
am wrong. I have checked on the errata section on the home page of
the book and could not find these there.
I have a suggestion for the general rules given on page 225 for the
electronic circuit domain
Rules 4,5 do not limit the number of input signal on the OR and AND
gates respectively and are general.
However rule 6 limits the number of Input signals on the XOR gate to 2
My suggesion is for the rule to be changed to the following in
keeping with the earlier rules
V g Type(g) = XOR => Signal (Out(1,g))=On <=>
ThereExists n1,n2 (Signal(In(n1,g)) <> Signal(In(n2,g))) And (n1<>n2)
Errata on Pg 192
Pg 192 Nested Qualifiers
"For all x and for all y, if x is the parent of y then y is the child
V x, y Parent (x, y) => Child (y, x)
According to the truth table Child (y, x) is true if Parent (x, y) is
true otherwise we do not make a statement about Child (y, x). This
allows the possibility that Child (y, x) be true i.e. "y is the child
of x" without `x' being the parent of `y'
The correct representation should have been
V x, y Parent (x, y) <=> Child (y, x)
V x, y Parent (x, y) And Child (y, x)
I am assuming the standard meaning of the predicates Child and Parent
There is a typo here the line in the book states
"Thus, we will are have two unary predicates"
this line is 8 th line from the bottom