Nuprl Lemma : unique-angles-in-half-plane
∀e:EuclideanPlane. ∀a,b,c,x,y,z:Point.
  (a # bc
  
⇒ x # yz
  
⇒ ((∃f:Point. (acb ≅a fzy ∧ (x leftof yz 
⇐⇒ f leftof yz) ∧ (x leftof zy 
⇐⇒ f leftof zy)))
     ∧ (∀f1,f2:Point.
          ((acb ≅a f1zy ∧ acb ≅a f2zy)
          
⇒ (((x leftof yz 
⇐⇒ f1 leftof yz) ∧ (x leftof zy 
⇐⇒ f1 leftof zy))
             ∧ (x leftof yz 
⇐⇒ f2 leftof yz)
             ∧ (x leftof zy 
⇐⇒ f2 leftof zy))
          
⇒ Colinear(z;f1;f2)))))
Proof
Definitions occuring in Statement : 
geo-cong-angle: abc ≅a xyz
, 
euclidean-plane: EuclideanPlane
, 
geo-colinear: Colinear(a;b;c)
, 
geo-lsep: a # bc
, 
geo-left: a leftof bc
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
Definitions unfolded in proof : 
so_apply: x[s1;s2;s3]
, 
so_lambda: so_lambda(x,y,z.t[x; y; z])
, 
append: as @ bs
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
decidable: Dec(P)
, 
ge: i ≥ j 
, 
nat: ℕ
, 
l_member: (x ∈ l)
, 
basic-geometry-: BasicGeometry-
, 
geo-cong-tri: Cong3(abc,a'b'c')
, 
geo-cong-angle: abc ≅a xyz
, 
uiff: uiff(P;Q)
, 
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
, 
geo-lsep: a # bc
, 
or: P ∨ Q
, 
geo-out: out(p ab)
, 
not: ¬A
, 
false: False
, 
exists: ∃x:A. B[x]
, 
basic-geometry: BasicGeometry
, 
rev_implies: P 
⇐ Q
, 
prop: ℙ
, 
uimplies: b supposing a
, 
guard: {T}
, 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
iff: P 
⇐⇒ Q
, 
cand: A c∧ B
, 
and: P ∧ Q
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
Lemmas referenced : 
int_formula_prop_less_lemma, 
intformless_wf, 
decidable__lt, 
list_ind_nil_lemma, 
list_ind_cons_lemma, 
l_member_wf, 
int_formula_prop_wf, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_le_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_and_lemma, 
istype-int, 
itermVar_wf, 
itermConstant_wf, 
intformle_wf, 
intformnot_wf, 
intformand_wf, 
full-omega-unsat, 
decidable__le, 
nat_properties, 
select_wf, 
length_wf, 
nil_wf, 
cons_wf, 
geo-colinear-append, 
left-convex2, 
geo-eq_inversion, 
Euclid-Prop7, 
geo-sep_wf, 
left-convex, 
geo-between_functionality, 
geo-eq_weakening, 
geo-congruent_functionality, 
geo-inner-five-segment, 
geo-construction-unicity, 
geo-congruent-refl, 
geo-between-symmetry, 
geo-inner-three-segment, 
geo-cong-angle-transitivity, 
geo-cong-angle-symm2, 
euclidean-plane-axioms, 
geo-between-trivial, 
geo-length-flip, 
geo-congruent_wf, 
cong3-in-half-plane, 
geo-congruent-iff-length, 
geo-add-length-between, 
geo-add-length_wf, 
squash_wf, 
true_wf, 
geo-length-type_wf, 
basic-geometry_wf, 
geo-add-length-comm, 
not-left-and-right, 
lsep-all-sym2, 
colinear-lsep-cycle, 
lsep-all-sym, 
geo-colinear-is-colinear-set, 
geo-between-implies-colinear, 
length_of_cons_lemma, 
length_of_nil_lemma, 
istype-false, 
istype-le, 
istype-less_than, 
geo-left-out, 
geo-between-sep, 
istype-void, 
geo-between_wf, 
geo-extend-exists, 
geo-sep-sym, 
lsep-implies-sep, 
geo-point_wf, 
geo-lsep_wf, 
geo-cong-angle_wf, 
geo-primitives_wf, 
euclidean-plane-structure_wf, 
euclidean-plane_wf, 
subtype_rel_transitivity, 
euclidean-plane-subtype, 
euclidean-plane-structure-subtype, 
geo-left_wf
Rules used in proof : 
int_eqEquality, 
approximateComputation, 
equalityIstype, 
setElimination, 
inlFormation_alt, 
lambdaEquality_alt, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
dependent_pairFormation_alt, 
promote_hyp, 
isect_memberEquality_alt, 
dependent_set_memberEquality_alt, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
unionElimination, 
voidElimination, 
dependent_functionElimination, 
independent_functionElimination, 
rename, 
inhabitedIsType, 
because_Cache, 
independent_isectElimination, 
instantiate, 
applyEquality, 
hypothesisEquality, 
isectElimination, 
extract_by_obid, 
introduction, 
universeIsType, 
functionIsType, 
productIsType, 
sqequalRule, 
thin, 
productElimination, 
sqequalHypSubstitution, 
hypothesis, 
independent_pairFormation, 
cut, 
lambdaFormation_alt, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}e:EuclideanPlane.  \mforall{}a,b,c,x,y,z:Point.
    (a  \#  bc
    {}\mRightarrow{}  x  \#  yz
    {}\mRightarrow{}  ((\mexists{}f:Point.  (acb  \mcong{}\msuba{}  fzy  \mwedge{}  (x  leftof  yz  \mLeftarrow{}{}\mRightarrow{}  f  leftof  yz)  \mwedge{}  (x  leftof  zy  \mLeftarrow{}{}\mRightarrow{}  f  leftof  zy)))
          \mwedge{}  (\mforall{}f1,f2:Point.
                    ((acb  \mcong{}\msuba{}  f1zy  \mwedge{}  acb  \mcong{}\msuba{}  f2zy)
                    {}\mRightarrow{}  (((x  leftof  yz  \mLeftarrow{}{}\mRightarrow{}  f1  leftof  yz)  \mwedge{}  (x  leftof  zy  \mLeftarrow{}{}\mRightarrow{}  f1  leftof  zy))
                          \mwedge{}  (x  leftof  yz  \mLeftarrow{}{}\mRightarrow{}  f2  leftof  yz)
                          \mwedge{}  (x  leftof  zy  \mLeftarrow{}{}\mRightarrow{}  f2  leftof  zy))
                    {}\mRightarrow{}  Colinear(z;f1;f2)))))
Date html generated:
2019_10_29-AM-09_18_40
Last ObjectModification:
2019_10_18-PM-04_51_29
Theory : euclidean!plane!geometry
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