Nuprl Lemma : fseg_nil
∀[T:Type]. ∀L:T List. (fseg(T;L;[]) 
⇐⇒ ↑null(L))
Proof
Definitions occuring in Statement : 
fseg: fseg(T;L1;L2)
, 
null: null(as)
, 
nil: []
, 
list: T List
, 
assert: ↑b
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
universe: Type
Definitions unfolded in proof : 
fseg: fseg(T;L1;L2)
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
implies: P 
⇒ Q
, 
assert: ↑b
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
top: Top
, 
bfalse: ff
, 
prop: ℙ
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
true: True
, 
not: ¬A
, 
false: False
, 
exists: ∃x:A. B[x]
, 
append: as @ bs
, 
so_lambda: so_lambda(x,y,z.t[x; y; z])
, 
so_apply: x[s1;s2;s3]
, 
uiff: uiff(P;Q)
, 
uimplies: b supposing a
Lemmas referenced : 
list_induction, 
iff_wf, 
exists_wf, 
list_wf, 
equal-wf-base-T, 
assert_wf, 
null_wf, 
null_nil_lemma, 
null_cons_lemma, 
append_wf, 
decidable__true, 
nil_wf, 
list_ind_nil_lemma, 
cons_wf, 
false_wf, 
decidable__false, 
btrue_wf, 
append_is_nil, 
and_wf, 
equal_wf, 
bfalse_wf, 
btrue_neq_bfalse
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
lambdaFormation, 
cut, 
thin, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
lambdaEquality, 
hypothesis, 
because_Cache, 
independent_functionElimination, 
rename, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
baseClosed, 
independent_pairFormation, 
unionElimination, 
natural_numberEquality, 
dependent_pairFormation, 
productElimination, 
equalitySymmetry, 
independent_isectElimination, 
dependent_set_memberEquality, 
equalityTransitivity, 
applyLambdaEquality, 
setElimination, 
addLevel, 
levelHypothesis
Latex:
\mforall{}[T:Type].  \mforall{}L:T  List.  (fseg(T;L;[])  \mLeftarrow{}{}\mRightarrow{}  \muparrow{}null(L))
Date html generated:
2018_05_21-PM-06_30_24
Last ObjectModification:
2018_05_19-PM-04_40_56
Theory : general
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