Nuprl Lemma : eu-middle_wf
∀[e:EuclideanStructure]. ∀[a,b:Point]. ∀[c:{c:Point| ¬Colinear(a;b;c)} ].  (middle(a;b;c) ∈ Point)
Proof
Definitions occuring in Statement : 
eu-middle: middle(a;b;c)
, 
eu-colinear: Colinear(a;b;c)
, 
eu-point: Point
, 
euclidean-structure: EuclideanStructure
, 
uall: ∀[x:A]. B[x]
, 
not: ¬A
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
eu-middle: middle(a;b;c)
, 
eu-point: Point
, 
euclidean-structure: EuclideanStructure
, 
record+: record+, 
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
, 
all: ∀x:A. B[x]
, 
eu-colinear: Colinear(a;b;c)
Lemmas referenced : 
subtype_rel_self, 
not_wf, 
equal_wf, 
uall_wf, 
iff_wf, 
isect_wf, 
set_wf, 
eu-point_wf, 
eu-colinear_wf, 
euclidean-structure_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
setElimination, 
thin, 
rename, 
sqequalRule, 
sqequalHypSubstitution, 
dependentIntersectionElimination, 
dependentIntersectionEqElimination, 
hypothesis, 
applyEquality, 
tokenEquality, 
instantiate, 
extract_by_obid, 
isectElimination, 
universeEquality, 
functionEquality, 
equalityTransitivity, 
equalitySymmetry, 
lambdaEquality, 
cumulativity, 
hypothesisEquality, 
because_Cache, 
setEquality, 
productEquality, 
productElimination, 
functionExtensionality, 
lambdaFormation, 
dependent_set_memberEquality, 
axiomEquality, 
isect_memberEquality
Latex:
\mforall{}[e:EuclideanStructure].  \mforall{}[a,b:Point].  \mforall{}[c:\{c:Point|  \mneg{}Colinear(a;b;c)\}  ].    (middle(a;b;c)  \mmember{}  Point)
Date html generated:
2016_10_26-AM-07_40_46
Last ObjectModification:
2016_09_20-PM-08_00_47
Theory : euclidean!geometry
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