Nuprl Lemma : div-search-lemma-ext
∀a:ℤ. ∀b:{a + 1...}. ∀f:ℤ ⟶ 𝔹.
  ∃x:{a..b-} [((∀y:{a..x + 1-}. (¬↑(f y))) ∧ (∀z:{x + 1..b + 1-}. (↑(f z))))] 
  supposing ∃x:{a..b-} [((∀y:{a..x + 1-}. (¬↑(f y))) ∧ (∀z:{x + 1..b + 1-}. (↑(f z))))]
Proof
Definitions occuring in Statement : 
int_upper: {i...}
, 
int_seg: {i..j-}
, 
assert: ↑b
, 
bool: 𝔹
, 
uimplies: b supposing a
, 
all: ∀x:A. B[x]
, 
sq_exists: ∃x:A [B[x]]
, 
not: ¬A
, 
and: P ∧ Q
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
add: n + m
, 
natural_number: $n
, 
int: ℤ
Definitions unfolded in proof : 
member: t ∈ T
, 
subtract: n - m
, 
genrec-ap: genrec-ap, 
ifthenelse: if b then t else f fi 
, 
div-search-lemma, 
divide-and-conquer, 
decidable__assert, 
uniform-comp-nat-induction, 
decidable__lt, 
decidable__squash, 
decidable__and, 
decidable__less_than', 
decidable_functionality, 
squash_elim, 
sq_stable_from_decidable, 
any: any x
, 
iff_preserves_decidability, 
sq_stable__from_stable, 
stable__from_decidable, 
uall: ∀[x:A]. B[x]
, 
so_lambda: so_lambda(x,y,z,w.t[x; y; z; w])
, 
so_apply: x[s1;s2;s3;s4]
, 
so_lambda: λ2x.t[x]
, 
top: Top
, 
so_apply: x[s]
, 
uimplies: b supposing a
Lemmas referenced : 
div-search-lemma, 
lifting-strict-decide, 
istype-void, 
strict4-decide, 
lifting-strict-less, 
divide-and-conquer, 
decidable__assert, 
uniform-comp-nat-induction, 
decidable__lt, 
decidable__squash, 
decidable__and, 
decidable__less_than', 
decidable_functionality, 
squash_elim, 
sq_stable_from_decidable, 
iff_preserves_decidability, 
sq_stable__from_stable, 
stable__from_decidable
Rules used in proof : 
introduction, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
cut, 
instantiate, 
extract_by_obid, 
hypothesis, 
sqequalRule, 
thin, 
sqequalHypSubstitution, 
equalityTransitivity, 
equalitySymmetry, 
isectElimination, 
baseClosed, 
Error :isect_memberEquality_alt, 
voidElimination, 
independent_isectElimination
Latex:
\mforall{}a:\mBbbZ{}.  \mforall{}b:\{a  +  1...\}.  \mforall{}f:\mBbbZ{}  {}\mrightarrow{}  \mBbbB{}.
    \mexists{}x:\{a..b\msupminus{}\}  [((\mforall{}y:\{a..x  +  1\msupminus{}\}.  (\mneg{}\muparrow{}(f  y)))  \mwedge{}  (\mforall{}z:\{x  +  1..b  +  1\msupminus{}\}.  (\muparrow{}(f  z))))] 
    supposing  \mexists{}x:\{a..b\msupminus{}\}  [((\mforall{}y:\{a..x  +  1\msupminus{}\}.  (\mneg{}\muparrow{}(f  y)))  \mwedge{}  (\mforall{}z:\{x  +  1..b  +  1\msupminus{}\}.  (\muparrow{}(f  z))))]
Date html generated:
2019_06_20-PM-01_15_56
Last ObjectModification:
2019_03_12-PM-09_04_30
Theory : int_2
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