Nuprl Lemma : geo-lt-angle-symm2
∀g:EuclideanPlane. ∀a,b,c,d,e,f:Point.  (abc < def ⇒ cba < def)
Proof
Definitions occuring in Statement : 
geo-lt-angle: abc < xyz, 
euclidean-plane: EuclideanPlane, 
geo-point: Point, 
all: ∀x:A. B[x], 
implies: P ⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
member: t ∈ T, 
prop: ℙ, 
uall: ∀[x:A]. B[x], 
subtype_rel: A ⊆r B, 
guard: {T}, 
uimplies: b supposing a, 
geo-lt-angle: abc < xyz, 
and: P ∧ Q, 
exists: ∃x:A. B[x], 
basic-geometry: BasicGeometry, 
cand: A c∧ B, 
geo-cong-angle: abc ≅a xyz
Lemmas referenced : 
geo-lt-angle_wf, 
geo-point_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
subtype_rel_transitivity, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
geo-cong-angle-preserves-lt-angle, 
geo-cong-angle-symm, 
euclidean-plane-axioms
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
universeIsType, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
inhabitedIsType, 
isectElimination, 
applyEquality, 
instantiate, 
independent_isectElimination, 
sqequalRule, 
independent_functionElimination, 
productElimination, 
independent_pairFormation, 
because_Cache
Latex:
\mforall{}g:EuclideanPlane.  \mforall{}a,b,c,d,e,f:Point.    (abc  <  def  {}\mRightarrow{}  cba  <  def)
Date html generated:
2019_10_16-PM-02_01_38
Last ObjectModification:
2019_09_12-AM-11_37_45
Theory : euclidean!plane!geometry
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