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Step * 1 of Lemma wfd-tree-cases


1. [A] : Type
2. w : wfd-tree(A)
3. ↑co-w-null(w)
⊢ (w = w-nil() ∈ wfd-tree(A)) ∨ ((¬↑co-w-null(w)) ∧ (w = mk-wfd-tree(wfd-subtrees(w)) ∈ wfd-tree(A)))
BY
{ (OrLeft THEN Auto) }

1
1. A : Type
2. w : wfd-tree(A)
3. ↑co-w-null(w)
⊢ w = w-nil() ∈ wfd-tree(A)

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Latex:

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Latex:

1.  [A]  :  Type
2.  w  :  wfd-tree(A)
3.  \muparrow{}co-w-null(w)
\mvdash{}  (w  =  w-nil())  \mvee{}  ((\mneg{}\muparrow{}co-w-null(w))  \mwedge{}  (w  =  mk-wfd-tree(wfd-subtrees(w))))


By

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Latex:
(OrLeft  THEN  Auto)

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