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Step * 1 of Lemma fset-ac-le-singleton-empty


1. T : Type
2. eq : EqDecider(T)@i
3. a : fset(fset(T))@i
⊢ fset-all(a;x.¬bfset-null({y ∈ {{}} | deq-f-subset(eq) y x}))
BY
{ (Using [`eq',⌜deq-fset(eq)⌝] (BLemma `fset-all-iff`)⋅ THEN Auto) }

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Latex:

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Latex:

1.  T  :  Type
2.  eq  :  EqDecider(T)@i
3.  a  :  fset(fset(T))@i
\mvdash{}  fset-all(a;x.\mneg{}\msubb{}fset-null(\{y  \mmember{}  \{\{\}\}  |  deq-f-subset(eq)  y  x\}))


By

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Latex:
(Using  [`eq',\mkleeneopen{}deq-fset(eq)\mkleeneclose{}]  (BLemma  `fset-all-iff`)\mcdot{}  THEN  Auto)

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