Nuprl Lemma : non-trivial-open-box
∀[X:CubicalSet]. ∀[I:Cname List]. ∀[J:nameset(I) List]. ∀[x:nameset(I)]. ∀[i:ℕ2].
  ∀bx:open_box(X;I;J;x;i). ∀y:nameset(J). ∀c:ℕ2.
    (¬(filter(λf.((dimension(f) =z y) ∧b (direction(f) =z c));bx)
    = []
    ∈ ({f:{f:I-face(X;I)| (f ∈ bx)} | ↑((dimension(f) =z y) ∧b (direction(f) =z c))}  List)))
Proof
Definitions occuring in Statement : 
open_box: open_box(X;I;J;x;i)
, 
face-direction: direction(f)
, 
face-dimension: dimension(f)
, 
I-face: I-face(X;I)
, 
cubical-set: CubicalSet
, 
nameset: nameset(L)
, 
coordinate_name: Cname
, 
l_member: (x ∈ l)
, 
filter: filter(P;l)
, 
nil: []
, 
list: T List
, 
band: p ∧b q
, 
int_seg: {i..j-}
, 
assert: ↑b
, 
eq_int: (i =z j)
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
not: ¬A
, 
set: {x:A| B[x]} 
, 
lambda: λx.A[x]
, 
natural_number: $n
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
open_box: open_box(X;I;J;x;i)
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
nameset: nameset(L)
, 
coordinate_name: Cname
, 
int_upper: {i...}
, 
int_seg: {i..j-}
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
false: False
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
so_apply: x[s]
, 
top: Top
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
band: p ∧b q
, 
ifthenelse: if b then t else f fi 
, 
uiff: uiff(P;Q)
, 
bfalse: ff
, 
l_exists: (∃x∈L. P[x])
, 
exists: ∃x:A. B[x]
, 
face-name: face-name(f)
, 
pi2: snd(t)
, 
pi1: fst(t)
, 
guard: {T}
, 
lelt: i ≤ j < k
, 
sq_stable: SqStable(P)
, 
squash: ↓T
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
less_than: a < b
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
cand: A c∧ B
, 
face-direction: direction(f)
, 
face-dimension: dimension(f)
, 
so_lambda: λ2x.t[x]
, 
sq_type: SQType(T)
Lemmas referenced : 
filter_type, 
I-face_wf, 
l_member_wf, 
band_wf, 
eq_int_wf, 
face-dimension_wf, 
face-direction_wf, 
list-subtype, 
list_wf, 
assert_wf, 
non_null_filter, 
int_seg_wf, 
not_wf, 
null_wf3, 
subtype_rel_list, 
top_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_eq_int, 
equal_wf, 
assert_of_null, 
equal-wf-T-base, 
nameset_wf, 
open_box_wf, 
coordinate_name_wf, 
cubical-set_wf, 
iff_transitivity, 
select_wf, 
int_seg_properties, 
length_wf, 
sq_stable__l_member, 
decidable__equal-coordinate_name, 
sq_stable__le, 
decidable__le, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
decidable__lt, 
intformless_wf, 
int_formula_prop_less_lemma, 
iff_weakening_uiff, 
assert_of_band, 
subtype_base_sq, 
set_subtype_base, 
lelt_wf, 
int_subtype_base, 
nameset_subtype_base, 
decidable__equal_int, 
intformeq_wf, 
int_formula_prop_eq_lemma
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
setEquality, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
lambdaEquality, 
applyEquality, 
because_Cache, 
sqequalRule, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
natural_numberEquality, 
independent_isectElimination, 
hyp_replacement, 
applyLambdaEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_functionElimination, 
unionElimination, 
equalityElimination, 
dependent_functionElimination, 
addLevel, 
impliesFunctionality, 
independent_pairFormation, 
baseClosed, 
dependent_pairFormation, 
imageMemberEquality, 
imageElimination, 
int_eqEquality, 
intEquality, 
computeAll, 
productEquality, 
promote_hyp, 
instantiate, 
cumulativity
Latex:
\mforall{}[X:CubicalSet].  \mforall{}[I:Cname  List].  \mforall{}[J:nameset(I)  List].  \mforall{}[x:nameset(I)].  \mforall{}[i:\mBbbN{}2].
    \mforall{}bx:open\_box(X;I;J;x;i).  \mforall{}y:nameset(J).  \mforall{}c:\mBbbN{}2.
        (\mneg{}(filter(\mlambda{}f.((dimension(f)  =\msubz{}  y)  \mwedge{}\msubb{}  (direction(f)  =\msubz{}  c));bx)  =  []))
Date html generated:
2017_10_05-AM-10_20_43
Last ObjectModification:
2017_07_28-AM-11_21_03
Theory : cubical!sets
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