Nuprl Lemma : geo-pt-swap-preserves-parallel
∀e:EuclideanPlane. ∀a,b,c,d:Point. ∀A:a ≠ b. ∀C:c ≠ d. ∀A':b ≠ a.  (<a, b, A> || <c, d, C> ⇒ <b, a, A'> || <c, d, C>)
Proof
Definitions occuring in Statement : 
geo-Aparallel: l || m, 
euclidean-plane: EuclideanPlane, 
geo-sep: a ≠ b, 
geo-point: Point, 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
pair: <a, b>
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
member: t ∈ T, 
squash: ↓T, 
uall: ∀[x:A]. B[x], 
prop: ℙ, 
geo-line: Line, 
subtype_rel: A ⊆r B, 
true: True, 
uimplies: b supposing a, 
guard: {T}, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
rev_implies: P ⇐ Q, 
geoline: LINE, 
so_lambda: λ2x y.t[x; y], 
so_apply: x[s1;s2], 
pi1: fst(t), 
pi2: snd(t), 
basic-geometry: BasicGeometry
Lemmas referenced : 
geo-Aparallel_wf, 
squash_wf, 
true_wf, 
geoline_wf, 
trivial-equal, 
geo-sep_wf, 
geo-point_wf, 
geoline-subtype1, 
iff_weakening_equal, 
euclidean-plane_wf, 
quotient-member-eq, 
geo-line_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
subtype_rel_transitivity, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
geo-line-eq_wf, 
geo-line-eq-equiv, 
geo-colinear-line-eq2, 
geo-colinear-same
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
applyEquality, 
thin, 
lambdaEquality, 
sqequalHypSubstitution, 
imageElimination, 
introduction, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
equalityTransitivity, 
hypothesis, 
equalitySymmetry, 
because_Cache, 
sqequalRule, 
dependent_pairEquality, 
productEquality, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
independent_isectElimination, 
productElimination, 
independent_functionElimination, 
dependent_functionElimination, 
instantiate
Latex:
\mforall{}e:EuclideanPlane.  \mforall{}a,b,c,d:Point.  \mforall{}A:a  \mneq{}  b.  \mforall{}C:c  \mneq{}  d.  \mforall{}A':b  \mneq{}  a.
    (<a,  b,  A>  ||  <c,  d,  C>  {}\mRightarrow{}  <b,  a,  A'>  ||  <c,  d,  C>)
Date html generated:
2018_05_22-PM-01_18_48
Last ObjectModification:
2018_05_11-PM-06_53_57
Theory : euclidean!plane!geometry
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