Nuprl Lemma : geo-Aax2
∀g:EuclideanPlane. ∀a,b:Point. ∀l,m:Line.  (a ≠ b ⇒ (a I l ∧ a I m) ⇒ (b I l ∧ b I m) ⇒ l ≡ m)
Proof
Definitions occuring in Statement : 
geo-incident: p I L, 
geo-line-eq: l ≡ m, 
geo-line: Line, 
euclidean-plane: EuclideanPlane, 
geo-sep: a ≠ b, 
geo-point: Point, 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
and: P ∧ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
and: P ∧ Q, 
geo-line: Line, 
pi1: fst(t), 
pi2: snd(t), 
geo-line-eq: l ≡ m, 
not: ¬A, 
geo-line-sep: geo-line-sep(g;l;m), 
exists: ∃x:A. B[x], 
member: t ∈ T, 
prop: ℙ, 
uall: ∀[x:A]. B[x], 
subtype_rel: A ⊆r B, 
guard: {T}, 
uimplies: b supposing a, 
uiff: uiff(P;Q), 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
false: False, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
oriented-plane: OrientedPlane, 
cand: A c∧ B, 
or: P ∨ Q, 
append: as @ bs, 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
top: Top, 
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, 
le: A ≤ B, 
less_than': less_than'(a;b), 
less_than: a < b, 
squash: ↓T, 
true: True, 
select: L[n], 
cons: [a / b], 
subtract: n - m
Lemmas referenced : 
geo-line-sep_wf, 
geo-sep_wf, 
geo-point_wf, 
geo-colinear_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
subtype_rel_transitivity, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
geo-line_wf, 
geo-incident-line, 
geo-incident_wf, 
geoline-subtype1, 
all_wf, 
geo-line-eq_wf, 
not-lsep-iff-colinear, 
oriented-colinear-append, 
cons_wf, 
nil_wf, 
cons_member, 
l_member_wf, 
equal_wf, 
exists_wf, 
geo-colinear-is-colinear-set, 
list_ind_cons_lemma, 
list_ind_nil_lemma, 
length_of_cons_lemma, 
length_of_nil_lemma, 
false_wf, 
lelt_wf
Rules used in proof : 
cut, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
sqequalHypSubstitution, 
productElimination, 
thin, 
sqequalRule, 
introduction, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
applyEquality, 
because_Cache, 
hypothesis, 
dependent_pairEquality, 
productEquality, 
instantiate, 
independent_isectElimination, 
dependent_functionElimination, 
addLevel, 
allFunctionality, 
impliesFunctionality, 
independent_pairFormation, 
andLevelFunctionality, 
lambdaEquality, 
cumulativity, 
universeEquality, 
functionEquality, 
independent_functionElimination, 
voidElimination, 
dependent_pairFormation, 
inrFormation, 
inlFormation, 
isect_memberEquality, 
voidEquality, 
dependent_set_memberEquality, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed
Latex:
\mforall{}g:EuclideanPlane.  \mforall{}a,b:Point.  \mforall{}l,m:Line.    (a  \mneq{}  b  {}\mRightarrow{}  (a  I  l  \mwedge{}  a  I  m)  {}\mRightarrow{}  (b  I  l  \mwedge{}  b  I  m)  {}\mRightarrow{}  l  \mequiv{}  m)
Date html generated:
2018_05_22-PM-01_19_01
Last ObjectModification:
2018_05_13-PM-11_21_37
Theory : euclidean!plane!geometry
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