Nuprl Lemma : face-of-intersection
∀k:ℕ. ∀a,b,b':ℚCube(k).  ((↑Inhabited(b')) 
⇒ (↑Inhabited(b)) 
⇒ (a ≤ b ∧ a ≤ b') 
⇒ a ≤ b ⋂ b')
Proof
Definitions occuring in Statement : 
inhabited-rat-cube: Inhabited(c)
, 
rat-cube-intersection: c ⋂ d
, 
rat-cube-face: c ≤ d
, 
rational-cube: ℚCube(k)
, 
nat: ℕ
, 
assert: ↑b
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uiff: uiff(P;Q)
, 
uimplies: b supposing a
, 
rat-cube-face: c ≤ d
, 
rat-cube-intersection: c ⋂ d
, 
cand: A c∧ B
, 
rational-cube: ℚCube(k)
, 
nat: ℕ
, 
prop: ℙ
, 
guard: {T}
, 
rational-interval: ℚInterval
, 
rat-interval-face: I ≤ J
, 
rat-interval-intersection: I ⋂ J
, 
rat-point-interval: [a]
, 
inhabited-rat-interval: Inhabited(I)
, 
or: P ∨ Q
, 
subtype_rel: A ⊆r B
, 
iff: P 
⇐⇒ Q
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
top: Top
, 
pi2: snd(t)
, 
pi1: fst(t)
, 
true: True
, 
rev_implies: P 
⇐ Q
, 
squash: ↓T
Lemmas referenced : 
assert-inhabited-rat-cube, 
int_seg_wf, 
rat-cube-face_wf, 
istype-assert, 
inhabited-rat-cube_wf, 
rational-cube_wf, 
istype-nat, 
rational-interval_wf, 
qle_wf, 
assert-q_le-eq, 
iff_weakening_equal, 
q_le_wf, 
pi2_wf, 
rationals_wf, 
pi1_wf_top, 
istype-void, 
equal_wf, 
or_wf, 
qmax_wf, 
qmin_wf, 
subtype_rel_self, 
squash_wf, 
true_wf, 
istype-universe, 
qmax-idempotent, 
qmin-idempotent, 
qmax-eq-iff-1, 
or_assoc, 
member_wf, 
qmax-eq-iff-2
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
sqequalHypSubstitution, 
productElimination, 
thin, 
cut, 
introduction, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
independent_isectElimination, 
dependent_functionElimination, 
sqequalRule, 
independent_pairFormation, 
applyEquality, 
inhabitedIsType, 
equalityIstype, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
universeIsType, 
natural_numberEquality, 
setElimination, 
rename, 
productIsType, 
unionIsType, 
independent_pairEquality, 
because_Cache, 
promote_hyp, 
unionElimination, 
applyLambdaEquality, 
lambdaEquality_alt, 
isect_memberEquality_alt, 
voidElimination, 
hyp_replacement, 
inlFormation_alt, 
inrFormation_alt, 
imageElimination, 
instantiate, 
universeEquality, 
imageMemberEquality, 
baseClosed
Latex:
\mforall{}k:\mBbbN{}.  \mforall{}a,b,b':\mBbbQ{}Cube(k).    ((\muparrow{}Inhabited(b'))  {}\mRightarrow{}  (\muparrow{}Inhabited(b))  {}\mRightarrow{}  (a  \mleq{}  b  \mwedge{}  a  \mleq{}  b')  {}\mRightarrow{}  a  \mleq{}  b  \mcap{}  b')
Date html generated:
2020_05_20-AM-09_20_29
Last ObjectModification:
2019_11_02-AM-10_59_05
Theory : rationals
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