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Zuhair Al-Johar
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Is the following sentence equivalent to $\sf AC$ over the rest of axioms of $\sf ZF$?

For each infinite set $X$: if for all $y \in X$ we have $|y| < |X|$, then $| \bigcup X|\leq |X| $?

Note: The cardinality function $||$ here is defined after Scott's.

If not, then to which of the known choice principles this is equivalent to?

This comes in connection to this question.

Is the following sentence equivalent to $\sf AC$ over the rest of axioms of $\sf ZF$?

For each infinite set $X$: if for all $y \in X$ we have $|y| < |X|$, then $| \bigcup X|\leq |X| $?

Note: The cardinality function $||$ here is defined after Scott's.

If not, then to which of the known choice principles this is equivalent to?

Is the following sentence equivalent to $\sf AC$ over the rest of axioms of $\sf ZF$?

For each infinite set $X$: if for all $y \in X$ we have $|y| < |X|$, then $| \bigcup X|\leq |X| $?

Note: The cardinality function $||$ here is defined after Scott's.

If not, then to which of the known choice principles this is equivalent to?

This comes in connection to this question.

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Zuhair Al-Johar
  • 11.3k
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  • 13
  • 47

Is "every infinite set of strictly subnumerous sets is equinumeroussupernumerous to its union" equivalent to AC?

Is the following sentence equivalent to $\sf AC$ over the rest of axioms of $\sf ZF$?

For each infinite set $X$: if for all $y \in X$ we have $|y| < |X|$, then $|X \cup \bigcup X|=|X| $$| \bigcup X|\leq |X| $?

Note: The cardinality function $||$ here is defined after Scott's.

If not, then to which of the known choice principles this is equivalent to?

Is "every infinite set of strictly subnumerous sets is equinumerous to its union" equivalent to AC?

Is the following sentence equivalent to $\sf AC$ over the rest of axioms of $\sf ZF$?

For each infinite set $X$: if for all $y \in X$ we have $|y| < |X|$, then $|X \cup \bigcup X|=|X| $?

Note: The cardinality function $||$ here is defined after Scott's.

If not, then to which of the known choice principles this is equivalent to?

Is "every infinite set of strictly subnumerous sets is supernumerous to its union" equivalent to AC?

Is the following sentence equivalent to $\sf AC$ over the rest of axioms of $\sf ZF$?

For each infinite set $X$: if for all $y \in X$ we have $|y| < |X|$, then $| \bigcup X|\leq |X| $?

Note: The cardinality function $||$ here is defined after Scott's.

If not, then to which of the known choice principles this is equivalent to?

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Source Link
Zuhair Al-Johar
  • 11.3k
  • 1
  • 13
  • 47

Is "every infinite set of strictly subnumerous sets is equinumerous to its union" equivalent to AC?

Is the following sentence equivalent to $\sf AC$ over the rest of axioms of $\sf ZF$?

For each infinite set $X$: if for all $y \in X$ we have $|y| < |X|$, then $|X \cup \bigcup X|=|X| $?

Note: The cardinality function $||$ here is defined after Scott's.

If not, then to which of the known choice principles this is equivalent to?