Nuprl Lemma : Euclid-Prop31
∀e:EuclideanPlane. ∀a,b,x:Point.  (a # b ⇒ x # ab ⇒ (∃y:Point. geo-parallel-points(e;a;b;x;y)))
Proof
Definitions occuring in Statement : 
geo-parallel-points: geo-parallel-points(e;a;b;c;d), 
euclidean-plane: EuclideanPlane, 
geo-lsep: a # bc, 
geo-sep: a # b, 
geo-point: Point, 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
implies: P ⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
subtype_rel: A ⊆r B, 
prop: ℙ, 
exists: ∃x:A. B[x], 
sq_exists: ∃x:A [B[x]], 
and: P ∧ Q, 
basic-geometry: BasicGeometry, 
guard: {T}, 
uimplies: b supposing a, 
euclidean-plane: EuclideanPlane, 
cand: A c∧ B, 
sq_stable: SqStable(P), 
squash: ↓T, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
not: ¬A, 
geo-perp-in: ab  ⊥x cd, 
basic-geometry-: BasicGeometry-, 
l_member: (x ∈ l), 
nat: ℕ, 
le: A ≤ B, 
less_than': less_than'(a;b), 
false: False, 
select: L[n], 
cons: [a / b], 
less_than: a < b, 
true: True, 
ge: i ≥ j , 
decidable: Dec(P), 
or: P ∨ Q, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
subtract: n - m, 
append: as @ bs, 
so_lambda: so_lambda3, 
so_apply: x[s1;s2;s3], 
geo-colinear-set: geo-colinear-set(e; L), 
l_all: (∀x∈L.P[x]), 
int_seg: {i..j-}, 
lelt: i ≤ j < k, 
geo-eq: a ≡ b
Latex:
\mforall{}e:EuclideanPlane.  \mforall{}a,b,x:Point.    (a  \#  b  {}\mRightarrow{}  x  \#  ab  {}\mRightarrow{}  (\mexists{}y:Point.  geo-parallel-points(e;a;b;x;y)))
Date html generated:
2020_05_20-AM-10_43_31
Last ObjectModification:
2020_01_13-PM-10_28_13
Theory : euclidean!plane!geometry
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