Nuprl Lemma : geo-cong-angle_weakening
∀e:BasicGeometry. ∀a,b,c:Point.  ((a ≠ b ∧ a ≡ c) ⇒ abc ≅a abc)
Proof
Definitions occuring in Statement : 
geo-cong-angle: abc ≅a xyz, 
basic-geometry: BasicGeometry, 
geo-eq: a ≡ b, 
geo-sep: a ≠ b, 
geo-point: Point, 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
and: P ∧ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
and: P ∧ Q, 
geo-cong-angle: abc ≅a xyz, 
cand: A c∧ B, 
member: t ∈ T, 
basic-geometry: BasicGeometry, 
uall: ∀[x:A]. B[x], 
uimplies: b supposing a, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
subtype_rel: A ⊆r B, 
guard: {T}, 
prop: ℙ, 
exists: ∃x:A. B[x]
Lemmas referenced : 
geo-sep-sym, 
geo-sep_functionality, 
geo-eq_inversion, 
geo-eq_weakening, 
geo-sep_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
basic-geometry-subtype, 
subtype_rel_transitivity, 
basic-geometry_wf, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
geo-eq_wf, 
geo-point_wf, 
geo-between-trivial, 
geo-congruent-refl, 
geo-between_wf, 
geo-congruent_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
sqequalHypSubstitution, 
productElimination, 
thin, 
cut, 
hypothesis, 
independent_pairFormation, 
introduction, 
extract_by_obid, 
dependent_functionElimination, 
because_Cache, 
independent_functionElimination, 
hypothesisEquality, 
isectElimination, 
independent_isectElimination, 
sqequalRule, 
productIsType, 
universeIsType, 
applyEquality, 
instantiate, 
inhabitedIsType, 
dependent_pairFormation_alt
Latex:
\mforall{}e:BasicGeometry.  \mforall{}a,b,c:Point.    ((a  \mneq{}  b  \mwedge{}  a  \mequiv{}  c)  {}\mRightarrow{}  abc  \mcong{}\msuba{}  abc)
Date html generated:
2019_10_16-PM-01_27_49
Last ObjectModification:
2018_11_07-PM-00_56_15
Theory : euclidean!plane!geometry
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