Nuprl Lemma : list-diff2-sym
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[as:T List]. ∀[b,c:T].  (as-[b; c] = as-[c]-[b] ∈ (T List))
Proof
Definitions occuring in Statement : 
list-diff: as-bs
, 
cons: [a / b]
, 
nil: []
, 
list: T List
, 
deq: EqDecider(T)
, 
uall: ∀[x:A]. B[x]
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
squash: ↓T
, 
prop: ℙ
, 
true: True
, 
subtype_rel: A ⊆r B
, 
uimplies: b supposing a
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
, 
append: as @ bs
, 
all: ∀x:A. B[x]
, 
so_lambda: so_lambda(x,y,z.t[x; y; z])
, 
top: Top
, 
so_apply: x[s1;s2;s3]
, 
or: P ∨ Q
Lemmas referenced : 
equal_wf, 
squash_wf, 
true_wf, 
list-diff_wf, 
cons_wf, 
nil_wf, 
list-diff-diff, 
iff_weakening_equal, 
list_ind_cons_lemma, 
list_ind_nil_lemma, 
list-diff_functionality, 
cons_member, 
member_singleton, 
or_wf, 
l_member_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
applyEquality, 
thin, 
lambdaEquality, 
sqequalHypSubstitution, 
imageElimination, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
equalityTransitivity, 
hypothesis, 
equalitySymmetry, 
because_Cache, 
cumulativity, 
natural_numberEquality, 
sqequalRule, 
imageMemberEquality, 
baseClosed, 
universeEquality, 
independent_isectElimination, 
productElimination, 
independent_functionElimination, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
axiomEquality, 
lambdaFormation, 
independent_pairFormation, 
addLevel, 
orFunctionality, 
promote_hyp, 
unionElimination, 
inrFormation, 
inlFormation
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[as:T  List].  \mforall{}[b,c:T].    (as-[b;  c]  =  as-[c]-[b])
Date html generated:
2017_04_17-AM-09_13_12
Last ObjectModification:
2017_02_27-PM-05_19_54
Theory : decidable!equality
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