Does Every Ordinal Have a Following Cardinal?

  • Thread starter Thread starter ibc
  • Start date Start date
  • Tags Tags
    Ordinal
ibc
Messages
80
Reaction score
0
(not assuming any kind of continuum hypothesis of course) does every cardinal have a following one, i.e a minimal cardinal that is strictly larger?edit: ops, the title should be "following cardinal"
 
Last edited:
Physics news on Phys.org
Yes (assuming the definition of cardinals as a special type of ordinals), it's the minimum of the class of ordinals with greater cardinality than your cardinal (this works because any initial segment of the class of ordinals is a set, and because the ordinals are well-ordered). If you don't want to assume the axiom of choice, you'll have to replace "cardinal" with "well-ordered cardinal".
 
Hi all, I've been a roulette player for more than 10 years (although I took time off here and there) and it's only now that I'm trying to understand the physics of the game. Basically my strategy in roulette is to divide the wheel roughly into two halves (let's call them A and B). My theory is that in roulette there will invariably be variance. In other words, if A comes up 5 times in a row, B will be due to come up soon. However I have been proven wrong many times, and I have seen some...
Thread 'Detail of Diagonalization Lemma'
The following is more or less taken from page 6 of C. Smorynski's "Self-Reference and Modal Logic". (Springer, 1985) (I couldn't get raised brackets to indicate codification (Gödel numbering), so I use a box. The overline is assigning a name. The detail I would like clarification on is in the second step in the last line, where we have an m-overlined, and we substitute the expression for m. Are we saying that the name of a coded term is the same as the coded term? Thanks in advance.
Back
Top