Questions about real-valued measurable cardinals and the continuum

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The discussion centers on the implications of the continuum hypothesis (CH) in relation to real-valued measurable cardinals and measurable cardinals. It establishes that if CH is false, the power of the continuum, denoted as 20, is not necessarily real-valued measurable. The participants clarify that while the existence of a measurable cardinal does not violate CH, the existence of 20 being real-valued measurable is incorrect. The conversation concludes that the statements regarding the equiconsistency of these concepts require careful interpretation.

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nomadreid
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Putting the following three statements together:

(a) Assuming that the continuum hypothesis is false, the power of the continuum 2\aleph<sub>0</sub> is real-valued measurable.

(b) The existence of a real-valued measurable and the existence of a measurable (= real-valued measurable & inaccessible) cardinal are equiconsistent.

(c) If there exists a measurable cardinal, the continuum hypothesis is false.

it sounds like this would imply the following absurd statement:

(d) Assuming that the continuum hypothesis is false, the existence of 2\aleph<sub>0</sub> and the existence of a measurable cardinal are equiconsistent.

What is wrong? Is (a) incorrect, or am I putting these together wrong? If (a) is incorrect, is there a clear example to show why?
 
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I don't believe that ##(a)## is true. It is true that every real-valued measurable cardinal ##\kappa## is either measurable or ##\kappa\leq 2^{\aleph_0}##.

But this does not imply that ##2^{\aleph_0}## is always real-valued measurable, even if CH is false. Indeed, it is perfectly possible that ##2^{\aleph_0} = \aleph_2## and this cannot be real-valued measurable since it is not weakly inaccessible (since it is not a limit cardinal).

As for (c), didn't you mean to say real-valued measurable. I don't think the existence of a measurable cardinal itself violates CH.
 
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Thanks, micromass. Very informative answer. So, as you say, (a) is not true. As for (c) I was thinking of the violation of V=L, not the CH. Oops. So (c) is also not true. Also it would not have been true if I had put in "real valued measurable" where I put "measurable": at most I could have said that if the power of the continuum were real valued measurable, then CH would be false.
 

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