Nuprl Lemma : symmetry-preserves-right-angle
∀e:BasicGeometry. ∀a,b,c,c':Point.  (c=b=c' 
⇒ Rabc 
⇒ Rabc')
Proof
Definitions occuring in Statement : 
right-angle: Rabc
, 
geo-midpoint: a=m=b
, 
basic-geometry: BasicGeometry
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
Definitions unfolded in proof : 
uimplies: b supposing a
, 
guard: {T}
, 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
member: t ∈ T
, 
right-angle: Rabc
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
uiff: uiff(P;Q)
Lemmas referenced : 
Error :basic-geo-primitives_wf, 
Error :basic-geo-structure_wf, 
basic-geometry_wf, 
subtype_rel_transitivity, 
basic-geometry-subtype, 
geo-point_wf, 
right-angle_wf, 
geo-midpoint_wf, 
geo-midpoint-symmetry, 
geo-midpoint_functionality, 
geo-eq_weakening, 
geo-congruent_functionality, 
symmetric-point-unicity2, 
geo-congruent-iff-length
Rules used in proof : 
sqequalRule, 
independent_isectElimination, 
instantiate, 
applyEquality, 
because_Cache, 
hypothesis, 
hypothesisEquality, 
thin, 
isectElimination, 
extract_by_obid, 
introduction, 
cut, 
rename, 
sqequalHypSubstitution, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
independent_functionElimination, 
dependent_functionElimination, 
promote_hyp, 
equalitySymmetry, 
productElimination
Latex:
\mforall{}e:BasicGeometry.  \mforall{}a,b,c,c':Point.    (c=b=c'  {}\mRightarrow{}  Rabc  {}\mRightarrow{}  Rabc')
Date html generated:
2017_10_02-PM-06_40_56
Last ObjectModification:
2017_08_05-PM-04_47_29
Theory : euclidean!plane!geometry
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