minkwe wrote:Okidoki:
The paper is dealing with a pair of spin 1/2 particles moving in opposite directions such that measurements can be made on them yielding +1 or -1. If measured along the same axis on both arms, the results must be opposite.
This is summarized mathematically in Equation (1)?
A(a,λ) = ±1, B(a, λ) = ±1 (1)
Where lambda is a "more complete specification" of whatever it is that is responsible for the outcomes.
Note, that equation (1) applies to every theory, including QM.
No, it applies only to a class of theories named local realistic. QM is not realistic (that means, it does not specify

) nor local (in interpretations which have a collapse). That QM is not a theory of this type is written de facto explicitly by the open reference to the EPR criterion of reality and supporting the EPR conclusion that QM is incomplete, and a more complete description will be of this type:
Bell 1964 wrote:Since we can predict in advance the result of measuring any chosen component of

, by previously measuring the same
component of

, it follows that the result of any such measurement must actually be predetermined. Since the initial quantum mechanical wave
function does not determine the result of an individual measurement, this predetermination implies the possibility of a more complete specification of
the state.
Let this more complete specification be effected by means of parameters

minkwe wrote:We haven't imposed any restrictions on lambda at this point. Lambda could be a non-local mechanism or anything you like. But because we start the discussion saying the results are ±1, on either side, then equation (1) is universally true by definition.
It isn't, because it specifies a dependence. It differs, for example, from
A(a,b,λ) = ±1, B(a,b, λ) = ±1
that it does not allow a dependence on b of A, and on a of B.
minkwe wrote:Do you have any problem with my summary presentation up to this point. If you do, please complain loudly. If this is all good with you, could you please tell me what you think equation (2) represents.
Done loud enough. Anyway: Formula (2) already fixes the other point, which appears important here, that
 d\lambda)
does not depend nor on a, nor on b. This has not been mentioned in the text itself, because it has been considered as trivial - last but not least, it was clearly said that we talk about a predetermination of all measurement outcomes (following the EPR argument). The superdeterminism loophole is simply ignored here.
Joy Christian wrote:Moreover (and this is my main complaint against Bell), one simply cannot define functions like in eq. (1) without specifying the co-domains of the functions. What is defined in (1) is mathematically ill-defined. One must carefully define at least what the domains of the functions A and B are, and what their co-domains are (or is).
I think the domains and the codomain are defined sufficiently clear. This is a physics paper, not a mathematical one, thus, one has to take into account that the requirements for formal mathematics are lower, but once it is simple, even trivial, to recover the missing formalism, this does not pose a problem. In the text you find "where a is some unit vector", thus, the mathematician would formally write down

. The space of possible values of

is described by "It is a matter of indifference in the following whether

denotes a single variable or a set, or even a set of functions, and whether the variables are discrete or continuous", which makes clear that the space of possible values of

can arbitrary, but self-evident that it has to be fixed for a particular model.
Then, writing A(a,b,λ) = ±1 is a way a physicist writes down what a mathematician would write down as
\in \{-1,1\})
or more formal
: S^2\times\Lambda \to\mathbb{Z}_2)
.