Nuprl Lemma : r2-straightedge-compass
∀c,d,a:ℝ^2. ∀b:{b:ℝ^2| b ≠ a ∧ c_b_d} .
  ∃u:{u:ℝ^2| cu=cd ∧ a_b_u} 
   (∃v:ℝ^2 [(cv=cd ∧ v_b_u ∧ (¬((¬a_b_v) ∧ (¬b_v_a) ∧ (¬v_a_b))) ∧ (b ≠ d 
⇒ (v ≠ u ∧ u ≠ b ∧ v ≠ b)))])
Proof
Definitions occuring in Statement : 
rv-be: a_b_c
, 
real-vec-sep: a ≠ b
, 
rv-congruent: ab=cd
, 
real-vec: ℝ^n
, 
all: ∀x:A. B[x]
, 
sq_exists: ∃x:A [B[x]]
, 
exists: ∃x:A. B[x]
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
set: {x:A| B[x]} 
, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
prop: ℙ
, 
uall: ∀[x:A]. B[x]
, 
nat: ℕ
, 
le: A ≤ B
, 
and: P ∧ Q
, 
less_than': less_than'(a;b)
, 
false: False
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
sq_stable: SqStable(P)
, 
squash: ↓T
, 
exists: ∃x:A. B[x]
, 
real-vec: ℝ^n
, 
int_seg: {i..j-}
, 
subtype_rel: A ⊆r B
, 
real-vec-dist: d(x;y)
, 
real-vec-norm: ||x||
, 
real-vec-sub: X - Y
, 
nat_plus: ℕ+
, 
less_than: a < b
, 
true: True
, 
real: ℝ
, 
eq_int: (i =z j)
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
bfalse: ff
, 
uiff: uiff(P;Q)
, 
uimplies: b supposing a
, 
rev_uimplies: rev_uimplies(P;Q)
, 
req_int_terms: t1 ≡ t2
, 
top: Top
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
cand: A c∧ B
, 
real-vec-sep: a ≠ b
, 
rge: x ≥ y
, 
guard: {T}
, 
rv-congruent: ab=cd
, 
rv-be: a_b_c
, 
rv-between: a-b-c
, 
sq_exists: ∃x:A [B[x]]
Lemmas referenced : 
set_wf, 
real-vec_wf, 
false_wf, 
le_wf, 
real-vec-sep_wf, 
rv-be_wf, 
sq_stable__real-vec-sep, 
real_wf, 
ifthenelse_wf, 
eq_int_wf, 
radd_wf, 
rabs_wf, 
int-to-real_wf, 
int_seg_wf, 
req_wf, 
real-vec-dist_wf, 
exists_wf, 
rleq_wf, 
dot-product_wf, 
real-vec-sub_wf, 
rmul_wf, 
real-regular, 
rsub_wf, 
less_than_wf, 
regular-int-seq_wf, 
itermSubtract_wf, 
itermAdd_wf, 
itermMultiply_wf, 
itermVar_wf, 
itermConstant_wf, 
req-iff-rsub-is-0, 
req_functionality, 
r2-dot-product, 
req_weakening, 
real_polynomial_null, 
real_term_value_sub_lemma, 
real_term_value_add_lemma, 
real_term_value_mul_lemma, 
real_term_value_var_lemma, 
real_term_value_const_lemma, 
rsqrt_wf, 
dot-product-nonneg, 
square-nonneg, 
rsqrt-of-square, 
radd-non-neg, 
zero-rleq-rabs, 
rleq-int, 
rsqrt_functionality, 
rv-extend, 
real-vec-between_wf, 
rless_wf, 
rless_functionality, 
trivial-rless-radd, 
rless-int, 
rless_functionality_wrt_implies, 
rleq_weakening_equal, 
radd_functionality_wrt_rleq, 
sq_stable__rless, 
real-vec-dist-between, 
req_transitivity, 
radd_functionality, 
real-vec-dist-nonneg, 
rabs-bounds, 
radd-preserves-rless, 
rminus_wf, 
radd-rminus-both, 
itermMinus_wf, 
real_term_value_minus_lemma, 
rv-be-symmetry, 
not_wf, 
rv-between_wf, 
rless_transitivity2, 
real-vec-triangle-inequality, 
rless_transitivity1, 
real-vec-dist-symmetry, 
rless-implies-rless, 
rv-line-circle-3-ext, 
sq_stable__rv-be, 
rv-be-inner-trans, 
req_inversion, 
rv-congruent_wf, 
sq_exists_wf, 
rv-pos-angle_wf, 
rv-be-dist, 
rv-pos-angle-shift, 
rv-pos-angle-permute, 
rv-pos-angle-not-be, 
rv-pos-angle-symmetry, 
not-rv-pos-angle-implies2, 
rv-T-iff, 
rv-T_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
dependent_set_memberEquality, 
natural_numberEquality, 
sqequalRule, 
independent_pairFormation, 
hypothesis, 
hypothesisEquality, 
lambdaEquality, 
productEquality, 
because_Cache, 
setElimination, 
rename, 
dependent_functionElimination, 
productElimination, 
independent_functionElimination, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
dependent_pairFormation, 
applyEquality, 
setEquality, 
independent_isectElimination, 
approximateComputation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
equalityTransitivity, 
equalitySymmetry, 
functionEquality, 
impliesFunctionality, 
promote_hyp
Latex:
\mforall{}c,d,a:\mBbbR{}\^{}2.  \mforall{}b:\{b:\mBbbR{}\^{}2|  b  \mneq{}  a  \mwedge{}  c\_b\_d\}  .
    \mexists{}u:\{u:\mBbbR{}\^{}2|  cu=cd  \mwedge{}  a\_b\_u\} 
      (\mexists{}v:\mBbbR{}\^{}2  [(cv=cd
                      \mwedge{}  v\_b\_u
                      \mwedge{}  (\mneg{}((\mneg{}a\_b\_v)  \mwedge{}  (\mneg{}b\_v\_a)  \mwedge{}  (\mneg{}v\_a\_b)))
                      \mwedge{}  (b  \mneq{}  d  {}\mRightarrow{}  (v  \mneq{}  u  \mwedge{}  u  \mneq{}  b  \mwedge{}  v  \mneq{}  b)))])
Date html generated:
2018_05_22-PM-02_36_58
Last ObjectModification:
2018_05_18-AM-09_46_36
Theory : reals
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