Nuprl Lemma : geo-cong-preserves-bet-out
∀e:BasicGeometry. ∀a,b,c,a',b',c':Point.  (a_b_c 
⇒ ab ≅ a'b' 
⇒ ac ≅ a'c' 
⇒ out(a' b'c') 
⇒ a'_b'_c')
Proof
Definitions occuring in Statement : 
geo-out: out(p ab)
, 
basic-geometry: BasicGeometry
, 
geo-congruent: ab ≅ cd
, 
geo-between: a_b_c
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
Definitions unfolded in proof : 
guard: {T}
, 
false: False
, 
subtype_rel: A ⊆r B
, 
prop: ℙ
, 
not: ¬A
, 
uimplies: b supposing a
, 
stable: Stable{P}
, 
uall: ∀[x:A]. B[x]
, 
basic-geometry: BasicGeometry
, 
member: t ∈ T
, 
and: P ∧ Q
, 
geo-out: out(p ab)
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
true: True
, 
squash: ↓T
, 
uiff: uiff(P;Q)
, 
rev_implies: 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-out_wf, 
not_wf, 
geo-between_wf, 
stable__geo-between, 
geo-add-length-between, 
geo-add-length_wf, 
geo-mk-seg_wf, 
geo-length_wf, 
iff_weakening_equal, 
geo-length-type_wf, 
true_wf, 
squash_wf, 
equal_wf, 
geo-congruent-iff-length, 
geo-add-length-implies-eq-zero, 
geo-add-length-assoc, 
geo-add-length-is-zero, 
geo-zero-length-iff, 
geo-eq_weakening, 
geo-between_functionality, 
geo-between-trivial
Rules used in proof : 
instantiate, 
voidElimination, 
sqequalRule, 
because_Cache, 
applyEquality, 
independent_pairFormation, 
independent_functionElimination, 
independent_isectElimination, 
isectElimination, 
hypothesis, 
hypothesisEquality, 
rename, 
setElimination, 
dependent_functionElimination, 
extract_by_obid, 
introduction, 
cut, 
thin, 
productElimination, 
sqequalHypSubstitution, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
baseClosed, 
imageMemberEquality, 
natural_numberEquality, 
universeEquality, 
equalitySymmetry, 
equalityTransitivity, 
imageElimination, 
lambdaEquality
Latex:
\mforall{}e:BasicGeometry.  \mforall{}a,b,c,a',b',c':Point.
    (a\_b\_c  {}\mRightarrow{}  ab  \00D0  a'b'  {}\mRightarrow{}  ac  \00D0  a'c'  {}\mRightarrow{}  out(a'  b'c')  {}\mRightarrow{}  a'\_b'\_c')
Date html generated:
2017_10_02-PM-06_27_54
Last ObjectModification:
2017_08_05-PM-04_40_57
Theory : euclidean!plane!geometry
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