Nuprl Lemma : geo-out-cong-implies-eq
∀e:BasicGeometry. ∀a,b,x,y:Point.  (out(a bx) ⇒ out(a by) ⇒ ax ≅ ay ⇒ x ≡ y)
Proof
Definitions occuring in Statement : 
geo-out: out(p ab), 
basic-geometry: BasicGeometry, 
geo-eq: a ≡ b, 
geo-congruent: ab ≅ cd, 
geo-point: Point, 
all: ∀x:A. B[x], 
implies: P ⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
member: t ∈ T, 
basic-geometry: BasicGeometry, 
uall: ∀[x:A]. B[x], 
subtype_rel: A ⊆r B, 
exists: ∃x:A. B[x], 
and: P ∧ Q, 
geo-out: out(p ab), 
l_member: (x ∈ l), 
nat: ℕ, 
decidable: Dec(P), 
or: P ∨ Q, 
uimplies: b supposing a, 
not: ¬A, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
top: Top, 
prop: ℙ, 
false: False, 
select: L[n], 
cons: [a / b], 
cand: A c∧ B, 
less_than: a < b, 
squash: ↓T, 
less_than': less_than'(a;b), 
true: True, 
ge: i ≥ j , 
subtract: n - m, 
append: as @ bs, 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
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, 
euclidean-plane: EuclideanPlane, 
basic-geometry-: BasicGeometry-, 
guard: {T}, 
geo-eq: a ≡ b, 
geo-strict-between: a-b-c
Lemmas referenced : 
geo-colinear-append, 
cons_wf, 
geo-point_wf, 
nil_wf, 
decidable__le, 
full-omega-unsat, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
istype-int, 
int_formula_prop_not_lemma, 
istype-void, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_wf, 
istype-le, 
length_of_cons_lemma, 
length_of_nil_lemma, 
istype-less_than, 
length_wf, 
select_wf, 
nat_properties, 
intformand_wf, 
itermVar_wf, 
int_formula_prop_and_lemma, 
int_term_value_var_lemma, 
geo-sep_wf, 
l_member_wf, 
geo-colinear-is-colinear-set, 
geo-out-colinear, 
list_ind_cons_lemma, 
list_ind_nil_lemma, 
decidable__lt, 
intformless_wf, 
int_formula_prop_less_lemma, 
geo-colinear-cases, 
subtype_rel_self, 
basic-geometry-_wf, 
geo-eq_wf, 
stable_geo-eq, 
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-strict-between_wf, 
geo-congruent_wf, 
geo-out_wf, 
geo-sep-sym, 
geo-proper-extend-exists, 
geo-O_wf, 
geo-X_wf, 
geo-sep-O-X, 
geo-construction-unicity, 
euclidean-plane-axioms, 
geo-strict-between-sep3, 
geo-between-symmetry, 
geo-strict-between-implies-between, 
geo-between-outer-trans, 
geo-congruent-symmetry, 
geo-between-exchange3, 
geo-not-bet-and-out, 
geo-out_inversion, 
geo-out_transitivity
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
isectElimination, 
applyEquality, 
because_Cache, 
hypothesis, 
sqequalRule, 
independent_functionElimination, 
dependent_pairFormation_alt, 
independent_pairFormation, 
productElimination, 
dependent_set_memberEquality_alt, 
natural_numberEquality, 
unionElimination, 
independent_isectElimination, 
approximateComputation, 
lambdaEquality_alt, 
isect_memberEquality_alt, 
voidElimination, 
universeIsType, 
imageMemberEquality, 
baseClosed, 
inhabitedIsType, 
productIsType, 
setElimination, 
rename, 
equalityIstype, 
int_eqEquality, 
equalityTransitivity, 
equalitySymmetry, 
instantiate, 
functionIsType
Latex:
\mforall{}e:BasicGeometry.  \mforall{}a,b,x,y:Point.    (out(a  bx)  {}\mRightarrow{}  out(a  by)  {}\mRightarrow{}  ax  \mcong{}  ay  {}\mRightarrow{}  x  \mequiv{}  y)
Date html generated:
2019_10_16-PM-01_24_39
Last ObjectModification:
2019_03_14-PM-09_08_17
Theory : euclidean!plane!geometry
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