Re: truth/falsity of sentences in first-order logic

Charlie-Boo wrote:
H. J. Sander Bruggink wrote:
1. Find the object in the model which is denoted by the
term "1";

I said 1+1=2 not f2(f1(a1),f1(a1))=f1(f1(f1(a1)))

1 is the object in the system. a1 would be a term.

You seem to be confusing language and meaning.


2. find the binary function in the model which is denoted by
the function symbol "+";

+ is a binary function not a function symbol. f2 would be a function
symbol.

No, certainly not. A function is a relation (a set of
tuples) with some extra conditions. "+" is not a set of
tuples. It is a *name* for a set of tuples. That's why
it's a function *symbol*.

You are confusing language and meaning.

Analogy: I am not "Sander". Sander is a very common
name in the Netherlands. If my friends say "Sander",
they usually refer to me. But in different contexts, the
same name can refer to very different people. The same
applies to "+".

[snip]

(quantified: What
portion of books or articles that teach logic exclude it?
Depending on what you mean by "teach logic", I'd say 0%.

One example and you're wrong?

Yes. Please give ONE example of a book *that teaches
logic*, and does not explain models.

Suppose I claimed I was an expert in cooking, and that I,
in fact, revolutionized haute cuisine. But then, after
some time, it turns out that I can't even boil an egg.
Would you believe me?

If boiling an egg is required to revolutionize haute cuisine then logic
says the statement is false. But what does that have to do with the
price of tea in China? We're talking about verifying mathematical
assertions, not people's bragging rights. What's the point of that?

I thought it was a quite simple analogy. But apparently,
you aren't even able to understand the most simple
analogies.

groente
-- Sander
.