Nuprl Lemma : count-related-pairs
∀[T,S:Type]. ∀[K:T List]. ∀[L:S List]. ∀[R:T ⟶ S ⟶ 𝔹].
  (Σ(||filter(R t;L)|| | t ∈ K) = Σ(||filter(λt.(R t s);K)|| | s ∈ L) ∈ ℤ)
Proof
Definitions occuring in Statement : 
lsum: Σ(f[x] | x ∈ L), 
length: ||as||, 
filter: filter(P;l), 
list: T List, 
bool: 𝔹, 
uall: ∀[x:A]. B[x], 
apply: f a, 
lambda: λx.A[x], 
function: x:A ⟶ B[x], 
int: ℤ, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
subtype_rel: A ⊆r B, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
prop: ℙ, 
uimplies: b supposing a, 
all: ∀x:A. B[x], 
istype: istype(T), 
true: True, 
so_lambda: λ2x y.t[x; y], 
so_apply: x[s1;s2], 
squash: ↓T, 
guard: {T}, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
rev_implies: P ⇐ Q, 
implies: P ⇒ Q
Lemmas referenced : 
bool_wf, 
list_wf, 
istype-universe, 
subtype_rel_dep_function, 
l_member_wf, 
double-lsum-swap, 
ifthenelse_wf, 
equal_wf, 
squash_wf, 
true_wf, 
lsum_wf, 
istype-int, 
length-filter-lsum, 
subtype_rel_self, 
iff_weakening_equal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
functionIsType, 
universeIsType, 
hypothesisEquality, 
cut, 
introduction, 
extract_by_obid, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
inhabitedIsType, 
instantiate, 
universeEquality, 
intEquality, 
applyEquality, 
setElimination, 
rename, 
because_Cache, 
sqequalRule, 
lambdaEquality_alt, 
setEquality, 
setIsType, 
independent_isectElimination, 
lambdaFormation_alt, 
natural_numberEquality, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
imageMemberEquality, 
baseClosed, 
productElimination, 
independent_functionElimination
Latex:
\mforall{}[T,S:Type].  \mforall{}[K:T  List].  \mforall{}[L:S  List].  \mforall{}[R:T  {}\mrightarrow{}  S  {}\mrightarrow{}  \mBbbB{}].
    (\mSigma{}(||filter(R  t;L)||  |  t  \mmember{}  K)  =  \mSigma{}(||filter(\mlambda{}t.(R  t  s);K)||  |  s  \mmember{}  L))
Date html generated:
2020_05_19-PM-09_48_21
Last ObjectModification:
2019_11_12-PM-11_50_49
Theory : list_1
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