Nuprl Lemma : can-find-first-ext
∀[T:Type]. ∀L:T List. ∀P:{x:T| (x ∈ L)}  ⟶ 𝔹.  ((∃x:T [first-member(T;x;L;P)]) ∨ (∀x∈L.¬↑(P x)))
Proof
Definitions occuring in Statement : 
first-member: first-member(T;x;L;P)
, 
l_all: (∀x∈L.P[x])
, 
l_member: (x ∈ l)
, 
list: T List
, 
assert: ↑b
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
sq_exists: ∃x:A [B[x]]
, 
not: ¬A
, 
or: P ∨ Q
, 
set: {x:A| B[x]} 
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
member: t ∈ T
, 
ifthenelse: if b then t else f fi 
, 
subtract: n - m
, 
can-find-first2, 
can-find-first1-ext
Lemmas referenced : 
can-find-first2, 
can-find-first1-ext
Rules used in proof : 
introduction, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
cut, 
instantiate, 
extract_by_obid, 
hypothesis, 
sqequalRule, 
thin, 
sqequalHypSubstitution, 
equalityTransitivity, 
equalitySymmetry
Latex:
\mforall{}[T:Type].  \mforall{}L:T  List.  \mforall{}P:\{x:T|  (x  \mmember{}  L)\}    {}\mrightarrow{}  \mBbbB{}.    ((\mexists{}x:T  [first-member(T;x;L;P)])  \mvee{}  (\mforall{}x\mmember{}L.\mneg{}\muparrow{}(P  x)))
Date html generated:
2018_05_21-PM-06_34_45
Last ObjectModification:
2018_05_19-PM-04_41_05
Theory : general
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