Nuprl Lemma : geo-opp-side-iff
∀[e:BasicGeometry]. ∀[A,B,P,Q:Point].
  (P-AB-Q ⇐⇒ ((¬Colinear(A;B;P)) ∧ (¬Colinear(A;B;Q))) ∧ (¬P leftof AB ⇐⇒ ¬Q leftof BA))
Proof
Definitions occuring in Statement : 
geo-opp-side: P-AB-Q, 
basic-geometry: BasicGeometry, 
geo-colinear: Colinear(a;b;c), 
geo-left: a leftof bc, 
geo-point: Point, 
uall: ∀[x:A]. B[x], 
iff: P ⇐⇒ Q, 
not: ¬A, 
and: P ∧ Q
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
implies: P ⇒ Q, 
not: ¬A, 
false: False, 
subtype_rel: A ⊆r B, 
guard: {T}, 
uimplies: b supposing a, 
prop: ℙ, 
rev_implies: P ⇐ Q, 
geo-opp-side: P-AB-Q, 
geo-lsep: a # bc, 
or: P ∨ Q, 
all: ∀x:A. B[x], 
basic-geometry: BasicGeometry, 
geo-colinear-set: geo-colinear-set(e; L), 
l_all: (∀x∈L.P[x]), 
top: Top, 
int_seg: {i..j-}, 
lelt: i ≤ j < k, 
decidable: Dec(P), 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
exists: ∃x:A. B[x], 
select: L[n], 
cons: [a / b], 
subtract: n - m, 
stable: Stable{P}, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
cand: A c∧ B, 
geo-same-side: A,B-PQ
Lemmas referenced : 
geo-colinear_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
basic-geometry-subtype, 
subtype_rel_transitivity, 
basic-geometry_wf, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
geo-left_wf, 
istype-void, 
geo-opp-side_wf, 
geo-point_wf, 
stable__false, 
false_wf, 
or_wf, 
geo-lsep_wf, 
not_wf, 
not-lsep-iff-colinear, 
geo-colinear-is-colinear-set, 
length_of_cons_lemma, 
length_of_nil_lemma, 
decidable__le, 
full-omega-unsat, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
istype-int, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_wf, 
decidable__lt, 
intformless_wf, 
int_formula_prop_less_lemma, 
istype-le, 
istype-less_than, 
minimal-double-negation-hyp-elim, 
minimal-not-not-excluded-middle, 
exists_wf, 
and_wf, 
geo-between_wf, 
left-between, 
euclidean-plane-subtype-oriented, 
oriented-plane_wf, 
geo-between-symmetry, 
lsep-all-sym2, 
lsep-all-sym, 
geo-same-side-iff, 
not-left-and-right
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
independent_pairFormation, 
lambdaFormation_alt, 
thin, 
hypothesis, 
sqequalHypSubstitution, 
independent_functionElimination, 
voidElimination, 
universeIsType, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
applyEquality, 
instantiate, 
independent_isectElimination, 
sqequalRule, 
because_Cache, 
functionIsType, 
productElimination, 
productIsType, 
independent_pairEquality, 
lambdaEquality_alt, 
dependent_functionElimination, 
functionIsTypeImplies, 
inhabitedIsType, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
functionEquality, 
unionElimination, 
dependent_set_memberEquality_alt, 
natural_numberEquality, 
approximateComputation, 
dependent_pairFormation_alt, 
unionIsType
Latex:
\mforall{}[e:BasicGeometry].  \mforall{}[A,B,P,Q:Point].
    (P-AB-Q  \mLeftarrow{}{}\mRightarrow{}  ((\mneg{}Colinear(A;B;P))  \mwedge{}  (\mneg{}Colinear(A;B;Q)))  \mwedge{}  (\mneg{}P  leftof  AB  \mLeftarrow{}{}\mRightarrow{}  \mneg{}Q  leftof  BA))
Date html generated:
2019_10_16-PM-01_21_01
Last ObjectModification:
2018_12_11-PM-00_15_51
Theory : euclidean!plane!geometry
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