Nuprl Lemma : remove-first-member-implies
∀[T:Type]. ∀L:T List. ∀P:{x:T| (x ∈ L)}  ⟶ 𝔹. ∀x:T.  ((x ∈ remove-first(P;L)) ⇒ (x ∈ L))
Proof
Definitions occuring in Statement : 
remove-first: remove-first(P;L), 
l_member: (x ∈ l), 
list: T List, 
bool: 𝔹, 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
set: {x:A| B[x]} , 
function: x:A ⟶ B[x], 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
member: t ∈ T, 
so_lambda: λ2x.t[x], 
prop: ℙ, 
so_apply: x[s], 
remove-first: remove-first(P;L), 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
top: Top, 
so_apply: x[s1;s2;s3], 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
false: False, 
list_ind: list_ind, 
nil: [], 
it: ⋅, 
rev_implies: P ⇐ Q, 
or: P ∨ Q, 
uimplies: b supposing a, 
sq_type: SQType(T), 
guard: {T}, 
uiff: uiff(P;Q), 
ifthenelse: if b then t else f fi , 
btrue: tt, 
bfalse: ff, 
subtype_rel: A ⊆r B
Lemmas referenced : 
list_induction, 
all_wf, 
l_member_wf, 
bool_wf, 
remove-first_wf, 
list_wf, 
list_ind_nil_lemma, 
nil_member, 
nil_wf, 
list_ind_cons_lemma, 
cons_wf, 
cons_member, 
bool_cases, 
subtype_base_sq, 
bool_subtype_base, 
eqtt_to_assert, 
equal_wf, 
eqff_to_assert, 
assert_of_bnot, 
subtype_rel_dep_function, 
subtype_rel_sets, 
subtype_rel_self, 
set_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
thin, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality, 
functionEquality, 
setEquality, 
cumulativity, 
hypothesis, 
functionExtensionality, 
applyEquality, 
independent_functionElimination, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
productElimination, 
rename, 
because_Cache, 
inlFormation, 
dependent_set_memberEquality, 
equalityTransitivity, 
equalitySymmetry, 
unionElimination, 
instantiate, 
independent_isectElimination, 
inrFormation, 
setElimination, 
hyp_replacement, 
Error :applyLambdaEquality, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}L:T  List.  \mforall{}P:\{x:T|  (x  \mmember{}  L)\}    {}\mrightarrow{}  \mBbbB{}.  \mforall{}x:T.    ((x  \mmember{}  remove-first(P;L))  {}\mRightarrow{}  (x  \mmember{}  L))
Date html generated:
2016_10_21-AM-10_27_23
Last ObjectModification:
2016_07_12-AM-05_39_43
Theory : list_1
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