Nuprl Lemma : decidable__equal_list
∀[T:Type]. ((∀x,y:T.  Dec(x = y ∈ T)) ⇒ (∀xs,ys:T List.  Dec(xs = ys ∈ (T List))))
Proof
Definitions occuring in Statement : 
list: T List, 
decidable: Dec(P), 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
implies: P ⇒ Q, 
all: ∀x:A. B[x], 
member: t ∈ T, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
prop: ℙ, 
decidable: Dec(P), 
or: P ∨ Q, 
not: ¬A, 
and: P ∧ Q, 
top: Top, 
false: False, 
squash: ↓T, 
true: True, 
cand: A c∧ B, 
uimplies: b supposing a, 
ge: i ≥ j , 
subtype_rel: A ⊆r B
Lemmas referenced : 
tl_wf, 
reduce_tl_cons_lemma, 
top_wf, 
subtype_rel_list, 
length_cons_ge_one, 
length_wf, 
ge_wf, 
squash_wf, 
hd_wf, 
reduce_hd_cons_lemma, 
decidable__and2, 
cons_neq_nil, 
btrue_neq_bfalse, 
bfalse_wf, 
null_cons_lemma, 
null_wf, 
and_wf, 
btrue_wf, 
null_nil_lemma, 
not_wf, 
cons_wf, 
nil_wf, 
equal_wf, 
decidable_wf, 
list_wf, 
all_wf, 
list_induction
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
thin, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality, 
hypothesis, 
independent_functionElimination, 
because_Cache, 
rename, 
dependent_functionElimination, 
universeEquality, 
inlFormation, 
inrFormation, 
dependent_set_memberEquality, 
independent_pairFormation, 
equalityTransitivity, 
equalitySymmetry, 
applyEquality, 
setElimination, 
productElimination, 
setEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
unionElimination, 
imageElimination, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
introduction, 
independent_isectElimination
Latex:
\mforall{}[T:Type].  ((\mforall{}x,y:T.    Dec(x  =  y))  {}\mRightarrow{}  (\mforall{}xs,ys:T  List.    Dec(xs  =  ys)))
Date html generated:
2016_05_14-AM-07_39_53
Last ObjectModification:
2016_01_15-AM-08_36_41
Theory : list_1
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