Elementary point about measurable cards

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
2 replies · 2K views
nomadreid
Gold Member
Messages
1,779
Reaction score
258
Just refreshing my understanding of measurable cardinals, the first step (more questions may follow, but one step at a time) is to make sure I understand the conditions: one of them is

For a (an uncountable) measurable cardinal κ, there exists a non-trivial, 0-1-valued measure μ on P(κ) such that there exists an λ<κ such that for any sequence [Aα: α<λ ] of disjoint sets Aα whose elements are smaller-than-κ ordinals, μ([itex]\cup[/itex]{ Aα }) = ∑μ(Aα)

Would not this mean that there would be a β<λ such that μ(Aβ) = 1 and [itex]\forall[/itex]γ<λ, (γ≠ β [itex]\Rightarrow[/itex] μ(Aβ) = 0)?

If not, why not?

P.S. except of course for those sequences for which for all α in the set of indices of the sequence, μ(Aα)=0
 
Last edited:
Physics news on Phys.org