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13h
asked Is the critical point of an embedding of a model of set theory inaccessible in it?
14h
comment What's wrong with this proof of Schröder-Bernstein theorem?
The argument works, it is the same that can be found for example in Jech's "Set Theory". I think "analyze" just means checking it is correct here.
15h
comment Closeness of measures on a cardinal
I checked that for a two-step iteration by a normal measure, $V\to M_1 \to M_2$, the $k$ obtained from the map from $V$ to $M_2$ is the same as the map from $M_1$ to $M_2$. And the embedding of $V$ to $M_2$ is an ultrapower embedding for a product ultrapower on $\kappa\times \kappa$, but we could make that into an ultrapower on $\kappa$ with Gödel pairing. So in this case the critical point of $k$ is $j_1(\kappa)$ when $j_1:V\to M_1$ is the ultrapower embedding for the normal measure on $\kappa$.
23h
revised Looking for extender axioms
added 407 characters in body
1d
comment Looking for extender axioms
Haha, well English is not my native language, maybe the title sounds weird.
1d
revised Looking for extender axioms
edited tags
1d
asked Looking for extender axioms
1d
answered Finding a minimum of a function, measuring the sum of the squares of distance from some points of the $\mathbb{R}^n$
1d
comment Row rank$=$Column rank
Try computing $A\cdot e_i$ where $e_i$ is the vector with a 1 at the ith place and zeroes at all other places. Then use that every n-dimensional vector is a linear combination of the $e_i$ for $1\leq i \leq n$.
1d
answered $\omega_1$-closedness and fullness for $\searrow$ $\omega$-sequences
1d
comment $\omega_1$-closedness and fullness for $\searrow$ $\omega$-sequences
What comes to my mind concerning the first proof is: In the assumption needed to apply "fullness", we need a name $\rho_n$ for every $n<\omega$, but in your proof, you only use one name $\rho$. (*) is correct, but it doesn't enable you to apply the consequence for "full".
1d
awarded  Critic
1d
comment How many of each ticket were sold in one day?
Oh sorry. I didn't realize the question was that old. My bad.
1d
comment How many of each ticket were sold in one day?
It's not given that on day one and two the same number of each type of ticket was sold. So, different notation like $a_1,a_2$ etc. would be much clearer.
1d
comment Closeness of measures on a cardinal
Thank you for the contribution, Miha. Could you explain why $cof(cp(k))\leq \kappa^+$ ? I understand the rest.
1d
comment Limit of a recurrence
Take the limit on both sides of the equation for $b_{n+1}$. For the limit of the right side, use that square root is continuous.
Aug
26
revised Closeness of measures on a cardinal
edited tags
Aug
26
revised Closeness of measures on a cardinal
added 3 characters in body
Aug
26
asked Closeness of measures on a cardinal
Jul
8
awarded  Yearling