Nuprl Lemma : straight-angle-sum1_symm
∀e:EuclideanPlane. ∀a,b,c,x,y,z,i,j,k:Point.  (abc + xyz ≅ ijk 
⇒ x-y-z 
⇒ out(b ac))
Proof
Definitions occuring in Statement : 
hp-angle-sum: abc + xyz ≅ def
, 
geo-out: out(p ab)
, 
euclidean-plane: EuclideanPlane
, 
geo-strict-between: a-b-c
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
hp-angle-sum: abc + xyz ≅ def
, 
exists: ∃x:A. B[x]
, 
and: P ∧ Q
, 
geo-cong-angle: abc ≅a xyz
, 
cand: A c∧ B
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
uimplies: b supposing a
, 
basic-geometry-: BasicGeometry-
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
prop: ℙ
, 
basic-geometry: BasicGeometry
, 
geo-out: out(p ab)
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
geo-sep-sym, 
angle-cong-preserves-straight-angle, 
geo-between-symmetry, 
geo-strict-between-implies-between, 
geo-strict-between_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
subtype_rel_transitivity, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
hp-angle-sum_wf, 
geo-point_wf, 
angle-cong-preserves-zero-angle, 
geo-out_transitivity, 
geo-out_inversion, 
geo-out-iff-between1, 
geo-strict-between-sep3, 
extended-out-preserves-between, 
geo-between-inner-trans, 
geo-between-exchange3, 
geo-between-exchange4
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
sqequalHypSubstitution, 
productElimination, 
thin, 
cut, 
introduction, 
extract_by_obid, 
dependent_functionElimination, 
hypothesisEquality, 
independent_functionElimination, 
hypothesis, 
independent_pairFormation, 
because_Cache, 
isectElimination, 
independent_isectElimination, 
sqequalRule, 
universeIsType, 
applyEquality, 
instantiate, 
inhabitedIsType
Latex:
\mforall{}e:EuclideanPlane.  \mforall{}a,b,c,x,y,z,i,j,k:Point.    (abc  +  xyz  \mcong{}  ijk  {}\mRightarrow{}  x-y-z  {}\mRightarrow{}  out(b  ac))
Date html generated:
2019_10_16-PM-02_04_50
Last ObjectModification:
2019_06_24-AM-10_15_40
Theory : euclidean!plane!geometry
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