Nuprl Lemma : Euclid-Prop5_2
∀e:EuclideanPlane. ∀a,b,c,x,y:Point.  ((ISOΔ(a;b;c) ∧ a-b-x ∧ a-c-y) ⇒ xbc ≅a ycb)
Proof
Definitions occuring in Statement : 
geo-isosceles: ISOΔ(a;b;c), 
geo-cong-angle: abc ≅a xyz, 
euclidean-plane: EuclideanPlane, 
geo-strict-between: a-b-c, 
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, 
member: t ∈ T, 
subtype_rel: A ⊆r B, 
uall: ∀[x:A]. B[x], 
guard: {T}, 
uimplies: b supposing a, 
prop: ℙ, 
sq_exists: ∃x:A [B[x]], 
euclidean-plane: EuclideanPlane, 
sq_stable: SqStable(P), 
squash: ↓T, 
basic-geometry: BasicGeometry, 
exists: ∃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, 
le: A ≤ B, 
less_than': less_than'(a;b), 
false: False, 
not: ¬A, 
less_than: a < b, 
true: True, 
select: L[n], 
cons: [a / b], 
subtract: n - m, 
cand: A c∧ B, 
geo-isosceles: ISOΔ(a;b;c), 
uiff: uiff(P;Q), 
geo-tri: Triangle(a;b;c), 
geo-cong-tri: Cong3(abc,a'b'c'), 
iff: P ⇐⇒ Q
Lemmas referenced : 
segment-density-strict, 
geo-strict-between-sep3, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
subtype_rel_transitivity, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
geo-sep_wf, 
sq_stable__geo-strict-between, 
geo-proper-extend-exists, 
geo-strict-between-sep2, 
geo-isosceles_wf, 
geo-strict-between_wf, 
geo-point_wf, 
geo-strict-between-sym, 
geo-strict-between-trans, 
geo-strict-between-trans2, 
colinear-lsep, 
geo-sep-sym, 
geo-colinear-is-colinear-set, 
geo-strict-between-implies-colinear, 
length_of_cons_lemma, 
length_of_nil_lemma, 
false_wf, 
lelt_wf, 
colinear-lsep-cycle, 
lsep-all-sym, 
geo-strict-between-sep1, 
geo-congruent-iff-length, 
geo-add-length-between, 
geo-strict-between-implies-between, 
geo-add-length_wf, 
squash_wf, 
true_wf, 
geo-length-type_wf, 
basic-geometry_wf, 
Euclid-Prop4, 
lsep-implies-sep, 
euclidean-plane-axioms, 
geo-congruent-flip, 
geo-between-out, 
geo-out_weakening, 
geo-eq_weakening, 
cong-angle-out-aux2_1, 
geo-congruent-symmetry, 
geo-length-flip, 
geo-out-iff-between1, 
geo-between-outer-trans, 
geo-between-symmetry, 
geo-out_inversion
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
sqequalHypSubstitution, 
productElimination, 
thin, 
cut, 
introduction, 
extract_by_obid, 
dependent_functionElimination, 
hypothesisEquality, 
applyEquality, 
hypothesis, 
instantiate, 
isectElimination, 
independent_isectElimination, 
sqequalRule, 
because_Cache, 
independent_functionElimination, 
dependent_set_memberEquality, 
setElimination, 
rename, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
productEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
natural_numberEquality, 
independent_pairFormation, 
lambdaEquality, 
equalityTransitivity, 
equalitySymmetry
Latex:
\mforall{}e:EuclideanPlane.  \mforall{}a,b,c,x,y:Point.    ((ISO\mDelta{}(a;b;c)  \mwedge{}  a-b-x  \mwedge{}  a-c-y)  {}\mRightarrow{}  xbc  \mcong{}\msuba{}  ycb)
 Date html generated: 
2018_05_22-PM-00_08_20
 Last ObjectModification: 
2018_05_11-PM-01_17_42
Theory : euclidean!plane!geometry
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