Nuprl Lemma : geo-out-iff-colinear
∀e:BasicGeometry. ∀p,a,b:Point.  (out(p ab) 
⇐⇒ (Colinear(p;a;b) ∧ (¬a_p_b)) ∧ p ≠ a ∧ p ≠ b)
Proof
Definitions occuring in Statement : 
geo-out: out(p ab)
, 
basic-geometry: BasicGeometry
, 
geo-colinear: Colinear(a;b;c)
, 
geo-between: a_b_c
, 
geo-sep: a ≠ b
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
not: ¬A
, 
and: P ∧ Q
Definitions unfolded in proof : 
cand: A c∧ B
, 
basic-geometry: BasicGeometry
, 
rev_implies: P 
⇐ Q
, 
geo-out: out(p ab)
, 
uimplies: b supposing a
, 
guard: {T}
, 
subtype_rel: A ⊆r B
, 
subtract: n - m
, 
cons: [a / b]
, 
select: L[n]
, 
uall: ∀[x:A]. B[x]
, 
true: True
, 
squash: ↓T
, 
less_than: a < b
, 
prop: ℙ
, 
not: ¬A
, 
false: False
, 
less_than': less_than'(a;b)
, 
le: A ≤ B
, 
lelt: i ≤ j < k
, 
int_seg: {i..j-}
, 
top: Top
, 
l_all: (∀x∈L.P[x])
, 
geo-colinear-set: geo-colinear-set(e; L)
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
iff: P 
⇐⇒ Q
, 
all: ∀x:A. B[x]
Lemmas referenced : 
geo-point_wf, 
geo-sep_wf, 
not_wf, 
geo-colinear_wf, 
geo-out_wf, 
Error :basic-geo-primitives_wf, 
Error :basic-geo-structure_wf, 
basic-geometry_wf, 
subtype_rel_transitivity, 
basic-geometry-subtype, 
geo-between_wf, 
lelt_wf, 
false_wf, 
length_of_nil_lemma, 
length_of_cons_lemma, 
geo-out-colinear, 
geo-colinear-is-colinear-set, 
geo-sep-irrefl', 
geo-sep_functionality, 
geo-eq_weakening, 
geo-between_functionality, 
geo-between-same, 
geo-between-inner-trans, 
geo-between-symmetry, 
geo-sep-sym, 
geo-between-outer-trans, 
geo-between-exchange4, 
geo-colinear-implies
Rules used in proof : 
rename, 
setElimination, 
productEquality, 
productElimination, 
independent_isectElimination, 
instantiate, 
applyEquality, 
isectElimination, 
baseClosed, 
imageMemberEquality, 
natural_numberEquality, 
dependent_set_memberEquality, 
voidEquality, 
voidElimination, 
isect_memberEquality, 
sqequalRule, 
hypothesis, 
because_Cache, 
independent_functionElimination, 
hypothesisEquality, 
thin, 
dependent_functionElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
independent_pairFormation, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
promote_hyp
Latex:
\mforall{}e:BasicGeometry.  \mforall{}p,a,b:Point.    (out(p  ab)  \mLeftarrow{}{}\mRightarrow{}  (Colinear(p;a;b)  \mwedge{}  (\mneg{}a\_p\_b))  \mwedge{}  p  \mneq{}  a  \mwedge{}  p  \mneq{}  b)
Date html generated:
2017_10_02-PM-06_27_00
Last ObjectModification:
2017_08_05-PM-04_20_31
Theory : euclidean!plane!geometry
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