Nuprl Lemma : Euclid-drop-perp-ext
∀e:EuclideanPlane. ∀a:Point. ∀b:{b:Point| a # b} . ∀c:{c:Point| c # ab} .  (∃p:Point [(Colinear(a;b;p) ∧ ab  ⊥p pc)])
Proof
Definitions occuring in Statement : 
geo-perp-in: ab  ⊥x cd
, 
euclidean-plane: EuclideanPlane
, 
geo-colinear: Colinear(a;b;c)
, 
geo-lsep: a # bc
, 
geo-sep: a # b
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
sq_exists: ∃x:A [B[x]]
, 
and: P ∧ Q
, 
set: {x:A| B[x]} 
Definitions unfolded in proof : 
member: t ∈ T
, 
record-select: r.x
, 
geo-CCL: CCL(a;b;c;d)
, 
geo-CCR: geo-CCR(g;a;b;c;d)
, 
ifthenelse: if b then t else f fi 
, 
midpoint-construction: Mid(a;b)
, 
let: let, 
Euclid-drop-perp, 
Euclid-drop-perp-1, 
Euclid-drop-perp-0, 
sq_stable__colinear, 
sq_stable__from_stable, 
stable__geo-perp-in, 
colinear-equidistant-points-exist, 
geo-CC-2, 
geo-congruent-refl, 
geo-sep-sym, 
geo-sep-or, 
stable__and, 
stable__all, 
symmetric-point-construction, 
use-SC, 
sq_stable__geo-sep, 
geo-between-implies-colinear, 
geo-congruent-sep, 
geo-congruent-symmetry, 
geo-congruent-iff-length, 
sq_stable__and, 
sq_stable__geo-congruent, 
sq_stable__geo-between, 
sq_stable__all, 
basic-geo-sep-sym, 
sq_stable__geo-axioms, 
geo-ge-sep, 
geo-seg-congruent-iff-length, 
sq_stable-geo-axioms-if, 
sq_stable__geo-gt-prim, 
sq_stable__geo-lsep, 
any: any x
, 
uall: ∀[x:A]. B[x]
, 
so_lambda: so_lambda4, 
so_apply: x[s1;s2;s3;s4]
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
uimplies: b supposing a
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
Latex:
\mforall{}e:EuclideanPlane.  \mforall{}a:Point.  \mforall{}b:\{b:Point|  a  \#  b\}  .  \mforall{}c:\{c:Point|  c  \#  ab\}  .
    (\mexists{}p:Point  [(Colinear(a;b;p)  \mwedge{}  ab    \mbot{}p  pc)])
Date html generated:
2020_05_20-AM-10_04_33
Last ObjectModification:
2020_01_27-PM-07_08_00
Theory : euclidean!plane!geometry
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