Nuprl Lemma : geo-midpoint-diagonals-congruent2
∀e:BasicGeometry. ∀P,Q,R,S,P',Q',R',S',A:Point.  (((((P=A=P' ∧ Q=A=Q') ∧ R=A=R') ∧ S=A=S') ∧ PQ ≅ RS) 
⇒ P'Q' ≅ R'S')
Proof
Definitions occuring in Statement : 
geo-midpoint: a=m=b
, 
basic-geometry: BasicGeometry
, 
geo-congruent: ab ≅ cd
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
Definitions unfolded in proof : 
uimplies: b supposing a
, 
guard: {T}
, 
cand: A c∧ B
, 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
member: t ∈ T
, 
and: P ∧ Q
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
uiff: uiff(P;Q)
Lemmas referenced : 
geo-point_wf, 
Error :basic-geo-primitives_wf, 
Error :basic-geo-structure_wf, 
basic-geometry_wf, 
subtype_rel_transitivity, 
basic-geometry-subtype, 
geo-congruent_wf, 
geo-midpoint_wf, 
geo-midpoint-diagonals-congruent, 
geo-congruent-iff-length
Rules used in proof : 
sqequalRule, 
independent_isectElimination, 
instantiate, 
applyEquality, 
because_Cache, 
hypothesis, 
hypothesisEquality, 
isectElimination, 
extract_by_obid, 
introduction, 
cut, 
productEquality, 
thin, 
productElimination, 
sqequalHypSubstitution, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
independent_functionElimination, 
dependent_functionElimination, 
equalitySymmetry, 
equalityTransitivity
Latex:
\mforall{}e:BasicGeometry.  \mforall{}P,Q,R,S,P',Q',R',S',A:Point.
    (((((P=A=P'  \mwedge{}  Q=A=Q')  \mwedge{}  R=A=R')  \mwedge{}  S=A=S')  \mwedge{}  PQ  \00D0  RS)  {}\mRightarrow{}  P'Q'  \00D0  R'S')
Date html generated:
2017_10_02-PM-06_33_34
Last ObjectModification:
2017_08_05-PM-04_43_49
Theory : euclidean!plane!geometry
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