Nuprl Lemma : compatible-rat-intervals-iff
∀I,J:ℚInterval.
  ((↑Inhabited(I))
  ⇒ (↑Inhabited(J))
  ⇒ (↑Inhabited(I ⋂ J))
  ⇒ (I ⋂ J ≤ I ∧ I ⋂ J ≤ J ⇐⇒ (I = J ∈ ℚInterval) ∨ ((snd(I)) = (fst(J)) ∈ ℚ) ∨ ((snd(J)) = (fst(I)) ∈ ℚ)))
Proof
Definitions occuring in Statement : 
rat-interval-intersection: I ⋂ J, 
inhabited-rat-interval: Inhabited(I), 
rat-interval-face: I ≤ J, 
rational-interval: ℚInterval, 
rationals: ℚ, 
assert: ↑b, 
pi1: fst(t), 
pi2: snd(t), 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
implies: P ⇒ Q, 
or: P ∨ Q, 
and: P ∧ Q, 
equal: s = t ∈ T
Definitions unfolded in proof : 
assert: ↑b, 
bnot: ¬bb, 
exists: ∃x:A. B[x], 
it: ⋅, 
unit: Unit, 
bool: 𝔹, 
squash: ↓T, 
true: True, 
qmax: qmax(x;y), 
bfalse: ff, 
btrue: tt, 
ifthenelse: if b then t else f fi , 
uiff: uiff(P;Q), 
sq_type: SQType(T), 
false: False, 
not: ¬A, 
qmin: qmin(x;y), 
top: Top, 
so_apply: x[s], 
so_lambda: λ2x.t[x], 
rat-point-interval: [a], 
guard: {T}, 
uimplies: b supposing a, 
prop: ℙ, 
rev_implies: P ⇐ Q, 
subtype_rel: A ⊆r B, 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
or: P ∨ Q, 
and: P ∧ Q, 
iff: P ⇐⇒ Q, 
implies: P ⇒ Q, 
rat-interval-face: I ≤ J, 
pi1: fst(t), 
pi2: snd(t), 
inhabited-rat-interval: Inhabited(I), 
rat-interval-intersection: I ⋂ J, 
rational-interval: ℚInterval, 
all: ∀x:A. B[x]
Lemmas referenced : 
qle_antisymmetry, 
assert-bnot, 
bool_cases_sqequal, 
qmin-idempotent, 
qmax-idempotent, 
istype-universe, 
true_wf, 
squash_wf, 
equal_wf, 
qle_weakening_eq_qorder, 
qle_transitivity_qorder, 
subtype_rel_self, 
assert_of_bnot, 
iff_weakening_uiff, 
iff_transitivity, 
eqff_to_assert, 
eqtt_to_assert, 
bool_subtype_base, 
bool_wf, 
subtype_base_sq, 
bool_cases, 
not_wf, 
bnot_wf, 
assert_wf, 
istype-void, 
pi1_wf_top, 
rationals_wf, 
pi2_wf, 
rational-interval_wf, 
q_le_wf, 
istype-assert, 
iff_weakening_equal, 
assert-q_le-eq, 
qle_wf, 
rat-point-interval_wf, 
qmin_wf, 
qmax_wf
Rules used in proof : 
unionEquality, 
dependent_pairFormation_alt, 
equalityElimination, 
hyp_replacement, 
promote_hyp, 
baseClosed, 
imageMemberEquality, 
universeEquality, 
imageElimination, 
natural_numberEquality, 
cumulativity, 
instantiate, 
dependent_functionElimination, 
functionIsType, 
inlFormation_alt, 
inrFormation_alt, 
voidElimination, 
isect_memberEquality_alt, 
lambdaEquality_alt, 
applyLambdaEquality, 
unionElimination, 
independent_isectElimination, 
equalitySymmetry, 
equalityTransitivity, 
independent_functionElimination, 
universeIsType, 
inhabitedIsType, 
applyEquality, 
hypothesis, 
hypothesisEquality, 
isectElimination, 
extract_by_obid, 
introduction, 
independent_pairEquality, 
because_Cache, 
equalityIstype, 
unionIsType, 
productIsType, 
independent_pairFormation, 
cut, 
sqequalRule, 
thin, 
productElimination, 
sqequalHypSubstitution, 
lambdaFormation_alt, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}I,J:\mBbbQ{}Interval.
    ((\muparrow{}Inhabited(I))
    {}\mRightarrow{}  (\muparrow{}Inhabited(J))
    {}\mRightarrow{}  (\muparrow{}Inhabited(I  \mcap{}  J))
    {}\mRightarrow{}  (I  \mcap{}  J  \mleq{}  I  \mwedge{}  I  \mcap{}  J  \mleq{}  J  \mLeftarrow{}{}\mRightarrow{}  (I  =  J)  \mvee{}  ((snd(I))  =  (fst(J)))  \mvee{}  ((snd(J))  =  (fst(I)))))
Date html generated:
2019_10_29-AM-07_53_56
Last ObjectModification:
2019_10_19-AM-01_36_30
Theory : rationals
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