Nuprl Lemma : geo-not-left-convex
∀g:OrientedPlane. ∀a,b:Point.  IsConvex(x.¬x leftof ab)
Proof
Definitions occuring in Statement : 
geo-convex: IsConvex(x.P[x]), 
oriented-plane: OrientedPlane, 
geo-left: a leftof bc, 
geo-point: Point, 
all: ∀x:A. B[x], 
not: ¬A
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
member: t ∈ T, 
so_lambda: λ2x.t[x], 
uall: ∀[x:A]. B[x], 
subtype_rel: A ⊆r B, 
guard: {T}, 
uimplies: b supposing a, 
oriented-plane: OrientedPlane, 
euclidean-plane: EuclideanPlane, 
basic-geometry-: BasicGeometry-, 
so_apply: x[s], 
implies: P ⇒ Q, 
prop: ℙ, 
geo-convex: IsConvex(x.P[x]), 
not: ¬A, 
false: False, 
or: P ∨ Q, 
stable: Stable{P}, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
geo-lsep: a # bc, 
geo-colinear-set: geo-colinear-set(e; L), 
l_all: (∀x∈L.P[x]), 
top: Top, 
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, 
exists: ∃x:A. B[x], 
cand: A c∧ B, 
rev_implies: P ⇐ Q, 
append: as @ bs, 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
so_apply: x[s1;s2;s3], 
geo-eq: a ≡ b
Lemmas referenced : 
oriented-plane-axioms, 
all_wf, 
geo-point_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
oriented-plane-subtype, 
subtype_rel_transitivity, 
oriented-plane_wf, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
geo-convex_wf, 
subtype_rel_self, 
basic-geometry-_wf, 
not_wf, 
geo-left_wf, 
geo-left-axioms_wf, 
basic-geo-axioms_wf, 
istype-void, 
geo-between_wf, 
stable__false, 
false_wf, 
minimal-double-negation-hyp-elim, 
minimal-not-not-excluded-middle, 
geo-left-convex, 
not-left-and-right, 
not-lsep-iff-colinear, 
geo-lsep_wf, 
geo-between-symmetry, 
left-convex3, 
geo-colinear-is-colinear-set, 
length_of_cons_lemma, 
length_of_nil_lemma, 
istype-false, 
istype-le, 
istype-less_than, 
geo-sep_wf, 
oriented-colinear-append, 
cons_wf, 
nil_wf, 
cons_member, 
l_member_wf, 
left-implies-sep, 
list_ind_cons_lemma, 
list_ind_nil_lemma, 
geo-between-implies-colinear, 
geo-colinear_functionality, 
geo-eq_weakening, 
geo-left_functionality, 
geo-between_functionality, 
geo-between-same
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality_alt, 
isectElimination, 
applyEquality, 
hypothesis, 
instantiate, 
independent_isectElimination, 
because_Cache, 
inhabitedIsType, 
universeIsType, 
independent_functionElimination, 
voidElimination, 
functionIsType, 
unionEquality, 
functionEquality, 
unionIsType, 
unionElimination, 
productElimination, 
rename, 
isect_memberEquality_alt, 
dependent_set_memberEquality_alt, 
natural_numberEquality, 
independent_pairFormation, 
imageMemberEquality, 
baseClosed, 
productIsType, 
inlFormation_alt, 
dependent_pairFormation_alt, 
inrFormation_alt, 
equalityIsType1, 
promote_hyp
Latex:
\mforall{}g:OrientedPlane.  \mforall{}a,b:Point.    IsConvex(x.\mneg{}x  leftof  ab)
Date html generated:
2019_10_16-PM-01_40_18
Last ObjectModification:
2018_11_12-PM-04_02_51
Theory : euclidean!plane!geometry
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