Nuprl Lemma : vert-angles-congruent
∀e:HeytingGeometry. ∀b,a,a',c,c':Point.  (a-b-a' 
⇒ c-b-c' 
⇒ a # bc 
⇒ abc ≅a a'bc')
Proof
Definitions occuring in Statement : 
geo-triangle: a # bc
, 
heyting-geometry: HeytingGeometry
, 
geo-cong-angle: abc ≅a xyz
, 
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
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
uimplies: b supposing a
, 
prop: ℙ
, 
and: P ∧ Q
, 
cand: A c∧ B
, 
heyting-geometry: HeytingGeometry
, 
geo-colinear-set: geo-colinear-set(e; L)
, 
l_all: (∀x∈L.P[x])
, 
top: Top
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
false: False
, 
not: ¬A
, 
less_than: a < b
, 
squash: ↓T
, 
true: True
, 
select: L[n]
, 
cons: [a / b]
, 
subtract: n - m
, 
euclidean-plane: EuclideanPlane
, 
basic-geometry-: BasicGeometry-
Lemmas referenced : 
geo-triangle_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
heyting-geometry-subtype, 
subtype_rel_transitivity, 
heyting-geometry_wf, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
geo-strict-between_wf, 
geo-point_wf, 
geo-triangle-symmetry, 
sup-angles-preserve-congruence, 
geo-cong-angle-symm, 
euclidean-plane-subtype-basic, 
basic-geometry_wf, 
geo-strict-between-sep2, 
geo-triangle-colinear, 
geo-sep-sym, 
geo-strict-between-sep3, 
geo-colinear-is-colinear-set, 
geo-strict-between-implies-colinear, 
length_of_cons_lemma, 
istype-void, 
length_of_nil_lemma, 
istype-false, 
istype-le, 
istype-less_than, 
geo-strict-between-sym, 
subtype_rel_self, 
basic-geometry-_wf, 
euclidean-plane-axioms, 
geo-cong-angle-transitivity
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
universeIsType, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
applyEquality, 
hypothesis, 
instantiate, 
independent_isectElimination, 
sqequalRule, 
because_Cache, 
inhabitedIsType, 
independent_pairFormation, 
dependent_functionElimination, 
independent_functionElimination, 
productElimination, 
isect_memberEquality_alt, 
voidElimination, 
dependent_set_memberEquality_alt, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
productIsType
Latex:
\mforall{}e:HeytingGeometry.  \mforall{}b,a,a',c,c':Point.    (a-b-a'  {}\mRightarrow{}  c-b-c'  {}\mRightarrow{}  a  \#  bc  {}\mRightarrow{}  abc  \mcong{}\msuba{}  a'bc')
Date html generated:
2019_10_16-PM-02_09_03
Last ObjectModification:
2018_11_07-PM-01_08_50
Theory : euclidean!plane!geometry
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