Nuprl Lemma : eu-colinear-def
∀e:EuclideanStructure
  ∀[a,b,c:Point].
    (Colinear(a;b;c)
    
⇐⇒ (¬(a = b ∈ Point)) ∧ (¬((¬(c = a ∈ Point)) ∧ (¬(c = b ∈ Point)) ∧ (¬c-a-b) ∧ (¬a-c-b) ∧ (¬a-b-c))))
Proof
Definitions occuring in Statement : 
eu-colinear: Colinear(a;b;c)
, 
eu-between: a-b-c
, 
eu-point: Point
, 
euclidean-structure: EuclideanStructure
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
not: ¬A
, 
and: P ∧ Q
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
uall: ∀[x:A]. B[x]
, 
euclidean-structure: EuclideanStructure
, 
record+: record+, 
member: t ∈ T
, 
record-select: r.x
, 
subtype_rel: A ⊆r B
, 
eq_atom: x =a y
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
guard: {T}
, 
prop: ℙ
, 
spreadn: spread3, 
and: P ∧ Q
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
, 
uimplies: b supposing a
, 
eu-point: Point
, 
eu-between: a-b-c
, 
eu-colinear: Colinear(a;b;c)
Lemmas referenced : 
subtype_rel_self, 
not_wf, 
equal_wf, 
uall_wf, 
iff_wf, 
and_wf, 
isect_wf, 
eu-point_wf, 
euclidean-structure_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
isect_memberFormation, 
sqequalHypSubstitution, 
dependentIntersectionElimination, 
sqequalRule, 
dependentIntersectionEqElimination, 
thin, 
cut, 
hypothesis, 
applyEquality, 
tokenEquality, 
instantiate, 
lemma_by_obid, 
isectElimination, 
universeEquality, 
functionEquality, 
equalityTransitivity, 
equalitySymmetry, 
lambdaEquality, 
cumulativity, 
hypothesisEquality, 
because_Cache, 
setEquality, 
productEquality, 
productElimination, 
setElimination, 
rename, 
introduction
Latex:
\mforall{}e:EuclideanStructure
    \mforall{}[a,b,c:Point].
        (Colinear(a;b;c)  \mLeftarrow{}{}\mRightarrow{}  (\mneg{}(a  =  b))  \mwedge{}  (\mneg{}((\mneg{}(c  =  a))  \mwedge{}  (\mneg{}(c  =  b))  \mwedge{}  (\mneg{}c-a-b)  \mwedge{}  (\mneg{}a-c-b)  \mwedge{}  (\mneg{}a-b-c))))
Date html generated:
2016_05_18-AM-06_32_43
Last ObjectModification:
2015_12_28-AM-09_28_28
Theory : euclidean!geometry
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