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Step * 1 of Lemma oob-getleft_wf


1. B : Type
2. A : Type
3. x : one_or_both(A;B)
4. ↑oob-hasleft(x)
5. ¬↑oobleft?(x)
⊢ ↑oobboth?(x)
BY
{ (Unfold `oob-hasleft` (-2) THEN (RW assert_pushdownC (-2) THENM D -2) THEN Auto) }

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Latex:

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Latex:

1.  B  :  Type
2.  A  :  Type
3.  x  :  one\_or\_both(A;B)
4.  \muparrow{}oob-hasleft(x)
5.  \mneg{}\muparrow{}oobleft?(x)
\mvdash{}  \muparrow{}oobboth?(x)


By

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Latex:
(Unfold  `oob-hasleft`  (-2)  THEN  (RW  assert\_pushdownC  (-2)  THENM  D  -2)  THEN  Auto)

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