Nuprl Lemma : l-last-is-last
∀[l:Top]. (l-last(l) ~ last(l))
Proof
Definitions occuring in Statement : 
l-last: l-last(l), 
last: last(L), 
uall: ∀[x:A]. B[x], 
top: Top, 
sqequal: s ~ t
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
all: ∀x:A. B[x], 
nat: ℕ, 
implies: P ⇒ Q, 
false: False, 
ge: i ≥ j , 
uimplies: b supposing a, 
not: ¬A, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
exists: ∃x:A. B[x], 
top: Top, 
and: P ∧ Q, 
prop: ℙ, 
or: P ∨ Q, 
cons: [a / b], 
le: A ≤ B, 
less_than': less_than'(a;b), 
colength: colength(L), 
nil: [], 
it: ⋅, 
guard: {T}, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
sq_type: SQType(T), 
less_than: a < b, 
squash: ↓T, 
so_lambda: λ2x y.t[x; y], 
so_apply: x[s1;s2], 
decidable: Dec(P), 
subtype_rel: A ⊆r B, 
bool: 𝔹, 
unit: Unit, 
btrue: tt, 
uiff: uiff(P;Q), 
ifthenelse: if b then t else f fi , 
bfalse: ff, 
bnot: ¬bb, 
assert: ↑b, 
rev_implies: P ⇐ Q, 
iff: P ⇐⇒ Q, 
list_ind: list_ind, 
l-last-default: l-last-default(l;d), 
l-last: l-last(l), 
cand: A c∧ B, 
is-exception: is-exception(t), 
has-value: (a)↓, 
strict4: strict4(F), 
so_apply: x[s1;s2;s3;s4], 
so_lambda: so_lambda(x,y,z,w.t[x; y; z; w]), 
nat_plus: ℕ+, 
select: L[n], 
last: last(L), 
true: True, 
label: ...$L... t, 
subtract: n - m, 
pi2: snd(t), 
pi1: fst(t), 
length: ||as||, 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
so_apply: x[s1;s2;s3], 
null: null(as)
Lemmas referenced : 
nat_properties, 
full-omega-unsat, 
intformand_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformless_wf, 
istype-int, 
int_formula_prop_and_lemma, 
istype-void, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
ge_wf, 
istype-less_than, 
top_wf, 
list-cases, 
l-last-nil, 
last_nil, 
product_subtype_list, 
colength-cons-not-zero, 
colength_wf_list, 
istype-false, 
le_wf, 
subtract-1-ge-0, 
subtype_base_sq, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
set_subtype_base, 
int_subtype_base, 
spread_cons_lemma, 
decidable__equal_int, 
subtract_wf, 
intformnot_wf, 
itermSubtract_wf, 
itermAdd_wf, 
int_formula_prop_not_lemma, 
int_term_value_subtract_lemma, 
int_term_value_add_lemma, 
decidable__le, 
l-last-cons, 
last_cons2, 
null_wf, 
eqtt_to_assert, 
assert_of_null, 
eqff_to_assert, 
bool_subtype_base, 
bool_cases_sqequal, 
bool_wf, 
assert-bnot, 
iff_weakening_uiff, 
assert_wf, 
equal-wf-T-base, 
list_wf, 
nat_wf, 
has-value-l-last-list, 
has-value_wf_base, 
is-exception_wf, 
has-value-last-list, 
istype-top, 
base_wf, 
sqle_wf_base, 
has-value-implies-dec-isaxiom-2, 
has-value-implies-dec-ispair-2, 
exception-not-bottom, 
bottom_diverge, 
lifting-strict-callbyvalue, 
fun_exp_unroll_1, 
exception-not-bottom_1, 
strictness-apply, 
fun_exp0_lemma, 
less_than_wf, 
satisfiable-full-omega-tt, 
equal-wf-base, 
equal_wf, 
assert_of_lt_int, 
lt_int_wf, 
length_of_cons_lemma, 
int-value-type, 
value-type-has-value, 
length-nat-if-has-value, 
false_wf, 
pair-eta, 
set-value-type, 
exception-not-value, 
length_of_nil_lemma, 
istype-base, 
decidable__lt, 
add-associates, 
add-swap, 
add-commutes, 
zero-add, 
length-zero-implies-nil, 
list_ind_cons_lemma, 
list_ind_nil_lemma, 
bfalse_wf, 
exception-not-value_1
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
sqequalRule, 
thin, 
Error :lambdaFormation_alt, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
intWeakElimination, 
natural_numberEquality, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
Error :dependent_pairFormation_alt, 
Error :lambdaEquality_alt, 
int_eqEquality, 
dependent_functionElimination, 
Error :isect_memberEquality_alt, 
voidElimination, 
independent_pairFormation, 
Error :universeIsType, 
axiomSqEquality, 
Error :functionIsTypeImplies, 
Error :inhabitedIsType, 
unionElimination, 
promote_hyp, 
hypothesis_subsumption, 
productElimination, 
Error :equalityIsType1, 
because_Cache, 
Error :dependent_set_memberEquality_alt, 
instantiate, 
equalityTransitivity, 
equalitySymmetry, 
applyLambdaEquality, 
imageElimination, 
Error :equalityIsType4, 
baseApply, 
closedConclusion, 
baseClosed, 
applyEquality, 
intEquality, 
equalityElimination, 
Error :equalityIsType3, 
cumulativity, 
sqequalSqle, 
divergentSqle, 
sqleReflexivity, 
lambdaFormation, 
axiomSqleEquality, 
exceptionSqequal, 
exceptionCompactness, 
callbyvalueReduce, 
callbyvalueExceptionCases, 
sqleRule, 
sqleTransitivity, 
inlFormation, 
inrFormation, 
applyExceptionCases, 
callbyvalueApply, 
dependent_set_memberEquality, 
imageMemberEquality, 
computeAll, 
voidEquality, 
isect_memberEquality, 
lambdaEquality, 
dependent_pairFormation, 
sqequalIntensionalEquality, 
productEquality, 
spreadExceptionCases, 
isect_memberFormation, 
lessCases, 
addEquality, 
callbyvalueAdd, 
lessExceptionCases, 
addExceptionCases, 
minusEquality, 
levelHypothesis, 
addLevel, 
Error :isectIsTypeImplies, 
callbyvalueCallbyvalue
Latex:
\mforall{}[l:Top].  (l-last(l)  \msim{}  last(l))
Date html generated:
2019_06_20-PM-01_20_47
Last ObjectModification:
2018_10_17-AM-11_51_01
Theory : list_1
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