Nuprl Lemma : inhabited-intersection-half-cubes
∀k:ℕ. ∀a,b,c,d:ℚCube(k).
  ((↑is-half-cube(k;c;a)) ⇒ (↑is-half-cube(k;d;b)) ⇒ (↑Inhabited(c ⋂ d)) ⇒ (↑Inhabited(a ⋂ b)))
Proof
Definitions occuring in Statement : 
inhabited-rat-cube: Inhabited(c), 
rat-cube-intersection: c ⋂ d, 
is-half-cube: is-half-cube(k;h;c), 
rational-cube: ℚCube(k), 
nat: ℕ, 
assert: ↑b, 
all: ∀x:A. B[x], 
implies: P ⇒ Q
Definitions unfolded in proof : 
squash: ↓T, 
qge: a ≥ b, 
true: True, 
lt_int: i <z j, 
qmul: r * s, 
qadd: r + s, 
qsub: r - s, 
qpositive: qpositive(r), 
bor: p ∨bq, 
q_le: q_le(r;s), 
qadd_grp: <ℚ+>, 
pi2: snd(t), 
pi1: fst(t), 
grp_le: ≤b, 
infix_ap: x f y, 
grp_leq: a ≤ b, 
qle: r ≤ s, 
false: False, 
assert: ↑b, 
eq_int: (i =z j), 
btrue: tt, 
evalall: evalall(t), 
callbyvalueall: callbyvalueall, 
qeq: qeq(r;s), 
not: ¬A, 
subtype_rel: A ⊆r B, 
qavg: qavg(a;b), 
ifthenelse: if b then t else f fi , 
band: p ∧b q, 
bfalse: ff, 
sq_type: SQType(T), 
rev_implies: P ⇐ Q, 
or: P ∨ Q, 
guard: {T}, 
is-half-interval: is-half-interval(I;J), 
inhabited-rat-interval: Inhabited(I), 
rat-interval-intersection: I ⋂ J, 
rational-interval: ℚInterval, 
cand: A c∧ B, 
rev_uimplies: rev_uimplies(P;Q), 
iff: P ⇐⇒ Q, 
prop: ℙ, 
rational-cube: ℚCube(k), 
nat: ℕ, 
rat-cube-intersection: c ⋂ d, 
uimplies: b supposing a, 
and: P ∧ Q, 
uiff: uiff(P;Q), 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
implies: P ⇒ Q, 
all: ∀x:A. B[x]
Lemmas referenced : 
qadd_inv_assoc_q, 
mon_ident_q, 
qinverse_q, 
qadd_ac_1_q, 
qadd_comm_q, 
qadd_preserves_qle, 
subtype_rel_self, 
qmul-qdiv-cancel, 
true_wf, 
squash_wf, 
qle_weakening_eq_qorder, 
qle_functionality_wrt_implies, 
int-subtype-rationals, 
qmul_wf, 
qle_witness, 
qadd_wf, 
qdiv_wf, 
qmul_preserves_qle2, 
qavg-qle-iff-1, 
qle-qavg-iff-1, 
assert_of_band, 
assert_of_bor, 
iff_transitivity, 
iff_weakening_equal, 
assert-q_le-eq, 
q_le_wf, 
rationals_wf, 
equal_wf, 
bfalse_wf, 
assert-qeq, 
btrue_wf, 
band_wf, 
eqtt_to_assert, 
bool_subtype_base, 
bool_wf, 
subtype_base_sq, 
bool_cases, 
qeq_wf2, 
bor_wf, 
qmax_lb, 
qmax_wf, 
qmin_ub, 
qmin_wf, 
qle_wf, 
qavg_wf, 
istype-nat, 
rational-cube_wf, 
assert-is-half-cube, 
is-half-cube_wf, 
assert_wf, 
iff_weakening_uiff, 
is-half-interval_wf, 
int_seg_wf, 
inhabited-rat-cube_wf, 
istype-assert, 
rat-cube-intersection_wf, 
assert-inhabited-rat-cube
Rules used in proof : 
minusEquality, 
universeEquality, 
imageMemberEquality, 
imageElimination, 
lambdaEquality_alt, 
isect_memberFormation_alt, 
sqequalBase, 
baseClosed, 
voidElimination, 
applyLambdaEquality, 
hyp_replacement, 
inrFormation_alt, 
inlFormation_alt, 
isect_memberEquality_alt, 
unionEquality, 
cumulativity, 
instantiate, 
unionElimination, 
promote_hyp, 
productEquality, 
unionIsType, 
productIsType, 
equalitySymmetry, 
equalityTransitivity, 
equalityIstype, 
inhabitedIsType, 
independent_pairFormation, 
dependent_functionElimination, 
functionEquality, 
independent_functionElimination, 
applyEquality, 
rename, 
setElimination, 
natural_numberEquality, 
universeIsType, 
functionIsType, 
sqequalRule, 
independent_isectElimination, 
productElimination, 
hypothesis, 
hypothesisEquality, 
because_Cache, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
lambdaFormation_alt, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}k:\mBbbN{}.  \mforall{}a,b,c,d:\mBbbQ{}Cube(k).
    ((\muparrow{}is-half-cube(k;c;a))  {}\mRightarrow{}  (\muparrow{}is-half-cube(k;d;b))  {}\mRightarrow{}  (\muparrow{}Inhabited(c  \mcap{}  d))  {}\mRightarrow{}  (\muparrow{}Inhabited(a  \mcap{}  b)))
Date html generated:
2019_10_29-AM-07_54_51
Last ObjectModification:
2019_10_22-PM-04_05_02
Theory : rationals
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