Nuprl Lemma : extend-half-cube-face
∀k:ℕ. ∀a,b,c:ℚCube(k).
  (0 < dim(c)
  ⇒ a ≤ b
  ⇒ (↑is-half-cube(k;b;c))
  ⇒ (dim(a) = (dim(b) - 1) ∈ ℤ)
  ⇒ (((∃!d:ℚCube(k). ((↑is-half-cube(k;a;d)) ∧ d ≤ c))
     ∧ (∀b':ℚCube(k). ((↑is-half-cube(k;b';c)) ⇒ a ≤ b' ⇒ (b' = b ∈ ℚCube(k)))))
     ∨ ((∃!b':ℚCube(k). (a ≤ b' ∧ (↑is-half-cube(k;b';c)) ∧ (¬(b' = b ∈ ℚCube(k))))) ∧ has-interior-point(k;a;c))))
Proof
Definitions occuring in Statement : 
rat-cube-dimension: dim(c), 
has-interior-point: has-interior-point(k;c;a), 
is-half-cube: is-half-cube(k;h;c), 
rat-cube-face: c ≤ d, 
rational-cube: ℚCube(k), 
nat: ℕ, 
assert: ↑b, 
less_than: a < b, 
exists!: ∃!x:T. P[x], 
all: ∀x:A. B[x], 
not: ¬A, 
implies: P ⇒ Q, 
or: P ∨ Q, 
and: P ∧ Q, 
subtract: n - m, 
natural_number: $n, 
int: ℤ, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
rat-cube-dimension: dim(c), 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
or: P ∨ Q, 
uimplies: b supposing a, 
sq_type: SQType(T), 
guard: {T}, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
ifthenelse: if b then t else f fi , 
btrue: tt, 
bfalse: ff, 
less_than: a < b, 
squash: ↓T, 
less_than': less_than'(a;b), 
false: False, 
nat: ℕ, 
ge: i ≥ j , 
decidable: Dec(P), 
not: ¬A, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
exists: ∃x:A. B[x], 
top: Top, 
prop: ℙ, 
immediate-rc-face: immediate-rc-face(k;f;c), 
int_seg: {i..j-}, 
lelt: i ≤ j < k, 
le: A ≤ B, 
true: True, 
subtype_rel: A ⊆r B, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
rational-cube: ℚCube(k), 
rational-interval: ℚInterval, 
rat-interval-dimension: dim(I), 
is-half-interval: is-half-interval(I;J), 
cand: A c∧ B, 
pi2: snd(t), 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
iff: P ⇐⇒ Q, 
bnot: ¬bb, 
assert: ↑b, 
rev_implies: P ⇐ Q, 
band: p ∧b q, 
rat-cube-face: c ≤ d, 
pi1: fst(t), 
exists!: ∃!x:T. P[x], 
rev_uimplies: rev_uimplies(P;Q), 
nequal: a ≠ b ∈ T , 
rat-point-interval: [a], 
rat-interval-face: I ≤ J, 
has-interior-point: has-interior-point(k;c;a), 
rat-point-in-cube: rat-point-in-cube(k;x;c), 
label: ...$L... t, 
inhabited-rat-interval: Inhabited(I)
Lemmas referenced : 
inhabited-rat-cube_wf, 
bool_cases, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
eqtt_to_assert, 
eqff_to_assert, 
assert_of_bnot, 
half-cube-dimension, 
istype-assert, 
nat_properties, 
decidable__lt, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformless_wf, 
itermConstant_wf, 
itermVar_wf, 
intformeq_wf, 
istype-int, 
int_formula_prop_and_lemma, 
istype-void, 
int_formula_prop_not_lemma, 
int_formula_prop_less_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_eq_lemma, 
int_formula_prop_wf, 
immediate-rc-face-implies, 
decidable__le, 
intformle_wf, 
itermSubtract_wf, 
int_formula_prop_le_lemma, 
int_term_value_subtract_lemma, 
rat-cube-dimension_wf, 
set_subtype_base, 
lelt_wf, 
int_subtype_base, 
subtract_wf, 
is-half-cube_wf, 
rat-cube-face_wf, 
istype-less_than, 
rational-cube_wf, 
istype-nat, 
assert-is-half-cube, 
rat-interval-dimension_wf, 
rational-interval_wf, 
rat-point-interval_wf, 
pi1_wf_top, 
rationals_wf, 
subtype_rel_product, 
top_wf, 
q_less_wf, 
assert-q_less-eq, 
iff_weakening_equal, 
bool_cases_sqequal, 
assert-bnot, 
qless_wf, 
qless-qavg-iff-1, 
qavg_wf, 
qavg-qless-iff-1, 
assert_wf, 
bor_wf, 
qeq_wf2, 
band_wf, 
btrue_wf, 
assert-qeq, 
bfalse_wf, 
equal_wf, 
ifthenelse_wf, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_bor, 
assert_of_band, 
assert-inhabited-rat-cube, 
rat-interval-face_wf, 
exists!_wf, 
int_seg_wf, 
not_wf, 
has-interior-point_wf, 
eq_int_wf, 
assert_of_eq_int, 
neg_assert_of_eq_int, 
assert_functionality_wrt_uiff, 
is-half-interval_wf, 
member_wf, 
qavg-eq-iff-1, 
squash_wf, 
true_wf, 
rat-interval-face-self, 
pi2_wf, 
istype-universe, 
qavg-same, 
subtype_rel_self, 
nequal_wf, 
qavg-eq-iff-4, 
decidable__equal_int, 
qavg-eq-iff-7, 
qavg-eq-iff-3, 
int_seg_properties, 
pair-eta, 
istype-top, 
qavg-eq-iff-2, 
qless_transitivity_2_qorder, 
qle_weakening_eq_qorder, 
qless_irreflexivity, 
decidable__equal_rational-interval, 
istype-le, 
rat-point-in-cube_wf, 
rat-point-in-cube-interior_wf, 
qle_reflexivity, 
qle_wf, 
qle-qavg-iff-1, 
qavg-qle-iff-1, 
q_le_wf, 
assert-q_le-eq, 
center-point-in-cube-interior
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
sqequalHypSubstitution, 
introduction, 
extract_by_obid, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
dependent_functionElimination, 
because_Cache, 
unionElimination, 
instantiate, 
cumulativity, 
independent_isectElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
productElimination, 
sqequalRule, 
imageElimination, 
voidElimination, 
dependent_set_memberEquality_alt, 
setElimination, 
rename, 
natural_numberEquality, 
approximateComputation, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
int_eqEquality, 
isect_memberEquality_alt, 
independent_pairFormation, 
universeIsType, 
promote_hyp, 
equalityIstype, 
applyEquality, 
intEquality, 
minusEquality, 
addEquality, 
inhabitedIsType, 
sqequalBase, 
productIsType, 
baseClosed, 
functionIsType, 
unionIsType, 
equalityElimination, 
hyp_replacement, 
applyLambdaEquality, 
unionEquality, 
productEquality, 
inlFormation_alt, 
inrFormation_alt, 
functionEquality, 
imageMemberEquality, 
functionExtensionality, 
independent_pairEquality, 
universeEquality
Latex:
\mforall{}k:\mBbbN{}.  \mforall{}a,b,c:\mBbbQ{}Cube(k).
    (0  <  dim(c)
    {}\mRightarrow{}  a  \mleq{}  b
    {}\mRightarrow{}  (\muparrow{}is-half-cube(k;b;c))
    {}\mRightarrow{}  (dim(a)  =  (dim(b)  -  1))
    {}\mRightarrow{}  (((\mexists{}!d:\mBbbQ{}Cube(k).  ((\muparrow{}is-half-cube(k;a;d))  \mwedge{}  d  \mleq{}  c))
          \mwedge{}  (\mforall{}b':\mBbbQ{}Cube(k).  ((\muparrow{}is-half-cube(k;b';c))  {}\mRightarrow{}  a  \mleq{}  b'  {}\mRightarrow{}  (b'  =  b))))
          \mvee{}  ((\mexists{}!b':\mBbbQ{}Cube(k).  (a  \mleq{}  b'  \mwedge{}  (\muparrow{}is-half-cube(k;b';c))  \mwedge{}  (\mneg{}(b'  =  b))))
              \mwedge{}  has-interior-point(k;a;c))))
Date html generated:
2020_05_20-AM-09_21_32
Last ObjectModification:
2019_11_02-PM-08_05_29
Theory : rationals
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