Nuprl Lemma : sqequal-nil
∀[T:Type]. ∀[l:T List].  l ~ [] supposing l = [] ∈ (T List)
Proof
Definitions occuring in Statement : 
nil: [], 
list: T List, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
universe: Type, 
sqequal: s ~ t, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uimplies: b supposing a, 
all: ∀x:A. B[x], 
or: P ∨ Q, 
cons: [a / b], 
assert: ↑b, 
ifthenelse: if b then t else f fi , 
btrue: tt, 
bfalse: ff, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
implies: P ⇒ Q, 
false: False, 
uiff: uiff(P;Q), 
top: Top, 
prop: ℙ, 
rev_implies: P ⇐ Q, 
true: True, 
not: ¬A
Lemmas referenced : 
list-cases, 
product_subtype_list, 
iff_imp_equal_bool, 
btrue_wf, 
bfalse_wf, 
assert_of_null, 
null_cons_lemma, 
istype-void, 
true_wf, 
false_wf, 
btrue_neq_bfalse, 
list_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
hypothesisEquality, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesis, 
dependent_functionElimination, 
unionElimination, 
promote_hyp, 
hypothesis_subsumption, 
productElimination, 
sqequalRule, 
independent_isectElimination, 
independent_pairFormation, 
Error :lambdaFormation_alt, 
equalityTransitivity, 
equalitySymmetry, 
Error :isect_memberEquality_alt, 
voidElimination, 
Error :universeIsType, 
natural_numberEquality, 
independent_functionElimination, 
axiomSqEquality, 
Error :equalityIsType3, 
Error :inhabitedIsType, 
baseClosed, 
because_Cache, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}[l:T  List].    l  \msim{}  []  supposing  l  =  []
Date html generated:
2019_06_20-PM-01_19_17
Last ObjectModification:
2018_09_30-PM-03_55_34
Theory : list_1
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