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Exercise 2100Logic, sets and proofs › Countability and cardinalityM1Added 3 Nov 2026

The generalized continuum hypothesis (statement)

#GCH#generalized continuum#set theory

Statement

State the generalized continuum hypothesis and its relation to CH.

Hint

GCH: for every infinite cardinal κ\kappa, 2κ=κ+2^\kappa=\kappa^+ (the next cardinal).

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Solution

GCH. 2κ=κ+2^\kappa=\kappa^+ for all infinite cardinals κ\kappa.

Special case. κ=ℵ0\kappa=\aleph_0: 2ℵ0=ℵ12^{\aleph_0}=\aleph_1, which is CH.

Independence. GCH is also independent of ZFC (Gödel, Cohen).

Conclusion. GCH generalizes CH to all infinite cardinals.