Nuprl Lemma : geo-krippen-aux
∀e:BasicGeometry. ∀a1,a2,b1,b2,c,m1,m2:Point.
  (a1_c_a2 
⇒ b1_c_b2 
⇒ ca1 ≅ cb1 
⇒ ca2 ≅ cb2 
⇒ a1=m1=b1 
⇒ a2=m2=b2 
⇒ |ca1| ≤ |ca2| 
⇒ m1_c_m2)
Proof
Definitions occuring in Statement : 
geo-le: p ≤ q
, 
geo-length: |s|
, 
geo-midpoint: a=m=b
, 
geo-mk-seg: 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 : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
basic-geometry: BasicGeometry
, 
euclidean-plane: EuclideanPlane
, 
uall: ∀[x:A]. B[x]
, 
stable: Stable{P}
, 
uimplies: b supposing a
, 
not: ¬A
, 
subtype_rel: A ⊆r B
, 
prop: ℙ
, 
or: P ∨ Q
, 
exists: ∃x:A. B[x]
, 
false: False
, 
geo-eq: a ≡ b
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
geo-midpoint: a=m=b
, 
cand: A c∧ B
, 
uiff: uiff(P;Q)
, 
geo-out: out(p ab)
, 
squash: ↓T
, 
true: True
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
Lemmas referenced : 
stable__geo-between, 
minimal-double-negation-hyp-elim, 
false_wf, 
or_wf, 
geo-sep_wf, 
not_wf, 
geo-between_wf, 
symmetric-point-construction, 
geo-sep-sym, 
geo-congruent-symmetry, 
geo-congruent-sep, 
geo-midpoint_functionality, 
geo-eq_weakening, 
geo-between_functionality, 
symmetric-point-unicity, 
geo-congruent_functionality, 
geo-between-trivial, 
minimal-not-not-excluded-middle, 
geo-congruence-identity, 
geo-midpoint-id2, 
geo-le_wf, 
geo-length_wf, 
geo-mk-seg_wf, 
geo-midpoint_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-between-symmetry, 
geo-midpoint-diagonals-between, 
geo-midpoint-diagonals-congruent2, 
geo-congruent-iff-length, 
geo-length-flip, 
and_wf, 
equal_wf, 
geo-length-type_wf, 
geo-sep-irrefl', 
geo-midpoint-id3, 
geo-between-trivial2, 
geo-sep_functionality, 
Error :basic-geo-primitives_wf, 
Error :basic-geo-structure_wf, 
geo-out-le-iff-bet, 
geo-between-same-side2, 
squash_wf, 
true_wf, 
geo-congruence-identity-sym, 
geo-between-outer-trans, 
not-not-double-pasch, 
exists_wf, 
double-negation-hyp-elim, 
geo-between-exchange3, 
geo-between-inner-trans, 
geo-congruent-refl, 
geo-inner-five-segment', 
at-most-one-midpoint, 
stable__geo-congruent, 
geo-colinear-between, 
geo-colinear-congruence1, 
geo-between-same
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
setElimination, 
rename, 
hypothesisEquality, 
hypothesis, 
isectElimination, 
independent_isectElimination, 
applyEquality, 
because_Cache, 
sqequalRule, 
functionEquality, 
independent_functionElimination, 
unionElimination, 
productElimination, 
voidElimination, 
promote_hyp, 
instantiate, 
independent_pairFormation, 
addLevel, 
hyp_replacement, 
equalitySymmetry, 
equalityTransitivity, 
dependent_set_memberEquality, 
applyLambdaEquality, 
levelHypothesis, 
lambdaEquality, 
imageElimination, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
productEquality
Latex:
\mforall{}e:BasicGeometry.  \mforall{}a1,a2,b1,b2,c,m1,m2:Point.
    (a1\_c\_a2  {}\mRightarrow{}  b1\_c\_b2  {}\mRightarrow{}  ca1  \00D0  cb1  {}\mRightarrow{}  ca2  \00D0  cb2  {}\mRightarrow{}  a1=m1=b1  {}\mRightarrow{}  a2=m2=b2  {}\mRightarrow{}  |ca1|  \mleq{}  |ca2|  {}\mRightarrow{}  m1\_c\_m2)
Date html generated:
2017_10_02-PM-06_35_38
Last ObjectModification:
2017_08_17-PM-08_12_20
Theory : euclidean!plane!geometry
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