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* and 1* - Quidquid latine dictum sit, altum videtur - TU Delft

* and 1* - Quidquid latine dictum sit, altum videtur - TU Delft

* and 1* - Quidquid latine dictum sit, altum videtur - TU Delft

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Scales<br />

History<br />

Some proofs<br />

Working toward 0 = 1<br />

A non-trivial autohomeomorphism<br />

Let κ > ω <strong>and</strong> assume ω ∗ <strong>and</strong> κ ∗ are homeomorphic.<br />

Consider ω × κ instead of κ <strong>and</strong> let γ : (ω × κ) ∗ → ω ∗ be a<br />

homeomorphism.<br />

Let Vn = {n} × κ <strong>and</strong> choose vn ⊆ ω such that v ∗ n = h[V ∗ n ].<br />

We may rearrange the vn to make them disjoint <strong>and</strong> even assume<br />

vn = {n} × ω for all n.<br />

Scales<br />

History<br />

Some proofs<br />

Working toward 0 = 1<br />

A non-trivial autohomeomorphism<br />

K. P. Hart ω ∗ <strong>and</strong> ω ∗ 1 13 / 30<br />

For α < κ let Eα = ω × [α, κ) <strong>and</strong> take eα ⊆ ω × ω such that<br />

e ∗ α = h[E ∗ α].<br />

Define fα : ω → ω by<br />

fα(n) = min{k : {n} × [k, ω) ⊆ eα}<br />

Note: fα ∗ fβ if α < β, i.e., {n : fα(n) > fβ(n)} is finite.<br />

For every f : ω → ω there is an α such that f ∗ fα.<br />

〈fα : α < κ〉 is a κ-scale.<br />

K. P. Hart ω ∗ <strong>and</strong> ω ∗ 1 14 / 30

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