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Step * 1 of Lemma Russell-paradox


1. 𝕌' ⊆r Type
⊢ Russell ∈ Russell
BY
{ TACTIC:MemTypeCD }

1
1. 𝕌' ⊆r Type
⊢ Russell ∈ Type ⋂ Base

2
.....set predicate..... 
1. 𝕌' ⊆r Type
⊢ ¬(Russell ∈ Russell)

3
.....wf..... 
1. 𝕌' ⊆r Type
2. T : Type ⋂ Base
⊢ istype(¬(T ∈ T))

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Latex:

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Latex:

1.  \mBbbU{}'  \msubseteq{}r  Type
\mvdash{}  Russell  \mmember{}  Russell


By

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Latex:
TACTIC:MemTypeCD

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