Nuprl Lemma : isleft-symmetry
∀g:OrientedPlane. ∀a,b:Point. ∀c:{c:Point| a # bc} .  isleft(a;b;c) = isleft(b;c;a)
Proof
Definitions occuring in Statement : 
geo-isleft: isleft(a;b;c), 
oriented-plane: OrientedPlane, 
geo-lsep: a # bc, 
geo-point: Point, 
bool: 𝔹, 
all: ∀x:A. B[x], 
set: {x:A| B[x]} , 
equal: s = t ∈ T
Definitions unfolded in proof : 
so_apply: x[s], 
so_lambda: λ2x.t[x], 
subtype_rel: A ⊆r B, 
rev_implies: P ⇐ Q, 
iff: P ⇐⇒ Q, 
uimplies: b supposing a, 
cand: A c∧ B, 
and: P ∧ Q, 
guard: {T}, 
implies: P ⇒ Q, 
prop: ℙ, 
oriented-plane: Error :oriented-plane, 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x]
Lemmas referenced : 
Error :basic-geo-primitives_wf, 
Error :basic-geo-structure_wf, 
basic-geometry-_wf, 
Error :oriented-plane_wf, 
subtype_rel_transitivity, 
Error :oriented-plane-subtype, 
basic-geometry--subtype, 
geo-point_wf, 
set_wf, 
iff_wf, 
assert_wf, 
assert-geo-isleft, 
geo-left_wf, 
left-symmetry, 
lsep-all-sym, 
geo-lsep_wf, 
geo-isleft_wf, 
iff_imp_equal_bool
Rules used in proof : 
lambdaEquality, 
sqequalRule, 
instantiate, 
applyEquality, 
impliesFunctionality, 
addLevel, 
independent_pairFormation, 
independent_isectElimination, 
productElimination, 
independent_functionElimination, 
dependent_functionElimination, 
because_Cache, 
dependent_set_memberEquality, 
hypothesis, 
hypothesisEquality, 
rename, 
setElimination, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}g:OrientedPlane.  \mforall{}a,b:Point.  \mforall{}c:\{c:Point|  a  \#  bc\}  .    isleft(a;b;c)  =  isleft(b;c;a)
Date html generated:
2017_10_02-PM-06_50_20
Last ObjectModification:
2017_08_06-PM-07_30_17
Theory : euclidean!plane!geometry
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