Nuprl Lemma : length_of_null_list
∀[A:Type]. ∀[as:A List].  ||as|| = 0 ∈ ℤ supposing as = [] ∈ (A List)
Proof
Definitions occuring in Statement : 
length: ||as||
, 
nil: []
, 
list: T List
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
natural_number: $n
, 
int: ℤ
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
prop: ℙ
Lemmas referenced : 
length_of_nil_lemma, 
equal-wf-T-base, 
length_wf, 
list_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
hypothesis, 
thin, 
sqequalRule, 
extract_by_obid, 
natural_numberEquality, 
hyp_replacement, 
equalitySymmetry, 
applyLambdaEquality, 
sqequalHypSubstitution, 
isectElimination, 
intEquality, 
hypothesisEquality, 
baseClosed, 
Error :universeIsType, 
isect_memberEquality, 
axiomEquality, 
because_Cache, 
equalityTransitivity, 
universeEquality
Latex:
\mforall{}[A:Type].  \mforall{}[as:A  List].    ||as||  =  0  supposing  as  =  []
Date html generated:
2019_06_20-PM-00_39_53
Last ObjectModification:
2018_09_26-PM-02_12_29
Theory : list_0
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