Nuprl Lemma : geo-le-pt-switch-congruence
∀e:BasicGeometry. ∀a,b,c,d:Point.  (a ≠ b 
⇒ ab≤cd 
⇒ cd≤ab 
⇒ ab ≅ cd)
Proof
Definitions occuring in Statement : 
geo-le-pt: ab≤cd
, 
basic-geometry: BasicGeometry
, 
geo-congruent: ab ≅ cd
, 
geo-sep: a ≠ b
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
Definitions unfolded in proof : 
uimplies: b supposing a
, 
guard: {T}
, 
subtype_rel: A ⊆r B
, 
basic-geometry: BasicGeometry
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
and: P ∧ Q
, 
exists: ∃x:A. B[x]
, 
geo-le-pt: ab≤cd
, 
uiff: uiff(P;Q)
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
, 
true: True
, 
squash: ↓T
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-sep_wf, 
geo-le-pt_wf, 
geo-le-pt-exists, 
geo-congruent-sep, 
geo-congruent-symmetry, 
geo-between-sep, 
geo-add-length-between, 
geo-eq_inversion, 
geo-congruent-iff-length, 
geo-between-exchange4, 
geo-between-exchange3, 
geo-between-inner-trans, 
geo-between-symmetry, 
geo-between-congruent, 
geo-length_functionality, 
geo-eq_weakening, 
iff_weakening_equal, 
geo-length-flip, 
true_wf, 
squash_wf, 
geo-mk-seg_wf, 
geo-length_wf, 
geo-length-type_wf, 
equal_wf, 
geo-add-length_wf, 
geo-add-length-assoc, 
geo-add-length-implies-eq2, 
geo-add-length-zero2
Rules used in proof : 
because_Cache, 
sqequalRule, 
independent_isectElimination, 
instantiate, 
applyEquality, 
hypothesis, 
hypothesisEquality, 
rename, 
setElimination, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
independent_functionElimination, 
dependent_functionElimination, 
productElimination, 
equalitySymmetry, 
equalityTransitivity, 
universeEquality, 
applyLambdaEquality, 
hyp_replacement, 
baseClosed, 
imageMemberEquality, 
natural_numberEquality, 
imageElimination, 
lambdaEquality
Latex:
\mforall{}e:BasicGeometry.  \mforall{}a,b,c,d:Point.    (a  \mneq{}  b  {}\mRightarrow{}  ab\mleq{}cd  {}\mRightarrow{}  cd\mleq{}ab  {}\mRightarrow{}  ab  \00D0  cd)
Date html generated:
2017_10_02-PM-06_46_37
Last ObjectModification:
2017_08_05-PM-04_51_28
Theory : euclidean!plane!geometry
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