Nuprl Lemma : colinear-lsep-alt
∀g:OrientedPlane. ∀a,b,c,x,z:Point. (a # bc ⇒ x ≠ b ⇒ Colinear(a;b;x) ⇒ z ≠ c ⇒ Colinear(x;c;z) ⇒ z # bc)
Proof
Definitions occuring in Statement :
oriented-plane: OrientedPlane,
geo-lsep: a # bc,
geo-colinear: Colinear(a;b;c),
geo-sep: a ≠ b,
geo-point: Point,
all: ∀x:A. B[x],
implies: P ⇒ Q
Definitions unfolded in proof :
uimplies: b supposing a,
guard: {T},
subtype_rel: A ⊆r B,
subtract: n - m,
cons: [a / b],
select: L[n],
uall: ∀[x:A]. B[x],
true: True,
squash: ↓T,
less_than: a < b,
prop: ℙ,
not: ¬A,
false: False,
less_than': less_than'(a;b),
le: A ≤ B,
and: P ∧ Q,
lelt: i ≤ j < k,
int_seg: {i..j-},
top: Top,
l_all: (∀x∈L.P[x]),
geo-colinear-set: geo-colinear-set(e; L),
oriented-plane: OrientedPlane,
member: t ∈ T,
implies: P ⇒ Q,
all: ∀x:A. B[x],
cand: A c∧ B
Lemmas referenced :
geo-point_wf,
geo-lsep_wf,
geo-sep_wf,
geo-primitives_wf,
euclidean-plane-structure_wf,
euclidean-plane_wf,
oriented-plane_wf,
subtype_rel_transitivity,
oriented-plane-subtype,
euclidean-plane-subtype,
euclidean-plane-structure-subtype,
geo-colinear_wf,
lelt_wf,
false_wf,
length_of_nil_lemma,
length_of_cons_lemma,
geo-colinear-is-colinear-set,
colinear-lsep,
lsep-all-sym
Rules used in proof :
independent_isectElimination,
instantiate,
applyEquality,
isectElimination,
baseClosed,
imageMemberEquality,
independent_pairFormation,
natural_numberEquality,
dependent_set_memberEquality,
voidEquality,
voidElimination,
isect_memberEquality,
sqequalRule,
because_Cache,
hypothesis,
independent_functionElimination,
hypothesisEquality,
thin,
dependent_functionElimination,
sqequalHypSubstitution,
extract_by_obid,
introduction,
cut,
lambdaFormation,
sqequalReflexivity,
computationStep,
sqequalTransitivity,
sqequalSubstitution,
productElimination
Latex:
\mforall{}g:OrientedPlane. \mforall{}a,b,c,x,z:Point.
(a \# bc {}\mRightarrow{} x \mneq{} b {}\mRightarrow{} Colinear(a;b;x) {}\mRightarrow{} z \mneq{} c {}\mRightarrow{} Colinear(x;c;z) {}\mRightarrow{} z \# bc)
Date html generated:
2017_10_02-PM-04_47_11
Last ObjectModification:
2017_08_07-AM-11_59_03
Theory : euclidean!plane!geometry
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