Nuprl Lemma : geo-congruent-preserves-out
∀e:BasicGeometry. ∀a,b,c,a',b',c':Point.  (bc ≅ b'c' 
⇒ ac ≅ a'c' 
⇒ ab ≅ a'b' 
⇒ out(a bc) 
⇒ out(a' b'c'))
Proof
Definitions occuring in Statement : 
geo-out: out(p ab)
, 
basic-geometry: BasicGeometry
, 
geo-congruent: ab ≅ cd
, 
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
, 
basic-geometry: BasicGeometry
, 
geo-colinear-set: geo-colinear-set(e; L)
, 
l_all: (∀x∈L.P[x])
, 
top: Top
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
and: P ∧ Q
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
false: False
, 
not: ¬A
, 
prop: ℙ
, 
less_than: a < b
, 
squash: ↓T
, 
true: True
, 
uall: ∀[x:A]. B[x]
, 
select: L[n]
, 
cons: [a / b]
, 
subtract: n - m
, 
geo-out: out(p ab)
, 
uimplies: b supposing a
, 
subtype_rel: A ⊆r B
, 
euclidean-plane: EuclideanPlane
, 
basic-geometry-: BasicGeometry-
, 
geo-eq: a ≡ b
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
uiff: uiff(P;Q)
, 
cand: A c∧ B
, 
geo-strict-between: a-b-c
Lemmas referenced : 
geo-colinear-is-colinear-set, 
geo-out-colinear, 
length_of_cons_lemma, 
length_of_nil_lemma, 
false_wf, 
lelt_wf, 
geo-congruent-symmetry, 
geo-congruent-sep, 
geo-colinear-cases, 
subtype_rel_self, 
basic-geometry-_wf, 
not_wf, 
geo-between_wf, 
stable__not, 
geo-eq_wf, 
geo-strict-between_wf, 
geo-colinear_wf, 
geo-out_wf, 
geo-congruent_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-point_wf, 
geo-congruence-identity, 
geo-between-trivial, 
geo-colinear_functionality, 
geo-eq_weakening, 
geo-between_functionality, 
geo-sep_functionality, 
geo-congruent_functionality, 
geo-sep-irrefl', 
geo-congruent-preserves-between, 
geo-strict-between-implies-between, 
geo-between-out, 
geo-congruent-iff-length, 
geo-length-flip, 
geo-between-symmetry, 
euclidean-plane-axioms, 
geo-sep-sym, 
geo-out_inversion, 
geo-not-bet-and-out
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
independent_functionElimination, 
because_Cache, 
hypothesis, 
sqequalRule, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
dependent_set_memberEquality, 
natural_numberEquality, 
independent_pairFormation, 
imageMemberEquality, 
baseClosed, 
isectElimination, 
productElimination, 
independent_isectElimination, 
applyEquality, 
instantiate, 
productEquality, 
comment, 
addLevel, 
impliesFunctionality, 
andLevelFunctionality, 
impliesLevelFunctionality, 
levelHypothesis, 
promote_hyp, 
equalityTransitivity, 
equalitySymmetry
Latex:
\mforall{}e:BasicGeometry.  \mforall{}a,b,c,a',b',c':Point.
    (bc  \mcong{}  b'c'  {}\mRightarrow{}  ac  \mcong{}  a'c'  {}\mRightarrow{}  ab  \mcong{}  a'b'  {}\mRightarrow{}  out(a  bc)  {}\mRightarrow{}  out(a'  b'c'))
Date html generated:
2018_05_22-AM-11_58_45
Last ObjectModification:
2018_04_06-PM-00_06_16
Theory : euclidean!plane!geometry
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