📕 subnode [[@karlicoss/logic]] in 📚 node [[logic]]

Table of Contents

[2017-11-30] Continuum hypothesis

Godel: proved that ZFC + CH is consistnent
Cohen: proved that ZFC + ~CH is consistnent (actually, any intermediate number of infinities)

[2015-08-26] depenedent sum

Sum (a : A) (B(A)) = {(a, b) | a ∈ A, b ∈ B(a)}
Exists (a : A) (B(A)) = || Sum a B ||

Self-reference elimination: use indices

x1 ∈ y2

y2 ∈ x1: forbidden!
x1 ∈ x2: forbidden!

System NF?

📖 stoas
⥱ context