Nuprl Lemma : implies-rv-pos-angle
∀n:ℕ. ∀a,b,c,a':ℝ^n.  (a-b-a' ⇒ ab=a'b ⇒ ab=cb ⇒ c ≠ a ⇒ c ≠ a' ⇒ rv-pos-angle(n;a;b;c))
Proof
Definitions occuring in Statement : 
rv-between: a-b-c, 
real-vec-sep: a ≠ b, 
rv-congruent: ab=cd, 
rv-pos-angle: rv-pos-angle(n;a;b;c), 
real-vec: ℝ^n, 
nat: ℕ, 
all: ∀x:A. B[x], 
implies: P ⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
rv-pos-angle: rv-pos-angle(n;a;b;c), 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
rv-congruent: ab=cd, 
real-vec-norm: ||x||, 
rsqrt: rsqrt(x), 
rroot: rroot(i;x), 
ifthenelse: if b then t else f fi , 
isEven: isEven(n), 
eq_int: (i =z j), 
modulus: a mod n, 
btrue: tt, 
rroot-abs: rroot-abs(i;x), 
fastexp: i^n, 
efficient-exp-ext, 
subtract: n - m, 
real-vec-dist: d(x;y), 
prop: ℙ, 
subtype_rel: A ⊆r B, 
uimplies: b supposing a, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
rev_implies: P ⇐ Q, 
real-vec-sep: a ≠ b, 
rv-between: a-b-c, 
real-vec-between: a-b-c, 
exists: ∃x:A. B[x], 
uiff: uiff(P;Q), 
rev_uimplies: rev_uimplies(P;Q), 
req-vec: req-vec(n;x;y), 
real-vec-sub: X - Y, 
real-vec-mul: a*X, 
real-vec-add: X + Y, 
nat: ℕ, 
real-vec: ℝ^n, 
req_int_terms: t1 ≡ t2, 
false: False, 
not: ¬A, 
top: Top, 
le: A ≤ B, 
less_than': less_than'(a;b), 
rneq: x ≠ y, 
or: P ∨ Q, 
guard: {T}, 
less_than: a < b, 
squash: ↓T, 
true: True, 
rdiv: (x/y), 
int_nzero: ℤ-o, 
nequal: a ≠ b ∈ T , 
sq_type: SQType(T)
Lemmas referenced : 
rv-pos-angle-lemma, 
real-vec-sub_wf, 
real-vec-sep_wf, 
rv-congruent_wf, 
rv-between_wf, 
real-vec_wf, 
istype-nat, 
int-to-real_wf, 
real-vec-dist_wf, 
rless_functionality, 
req_weakening, 
real-vec-dist-translation, 
real-vec-sep-symmetry, 
real-vec-add_wf, 
real-vec-mul_wf, 
rsub_wf, 
req_functionality, 
real-vec-dist_functionality, 
req-vec_weakening, 
req-vec_functionality, 
real-vec-mul_functionality, 
real-vec-sub_functionality, 
real-vec-dist-equal-iff, 
int_seg_wf, 
radd_wf, 
rmul_wf, 
itermSubtract_wf, 
itermVar_wf, 
itermAdd_wf, 
itermMultiply_wf, 
itermConstant_wf, 
req-iff-rsub-is-0, 
dot-product_wf, 
real_polynomial_null, 
istype-int, 
real_term_value_sub_lemma, 
istype-void, 
real_term_value_var_lemma, 
real_term_value_add_lemma, 
real_term_value_mul_lemma, 
real_term_value_const_lemma, 
dot-product_functionality, 
rminus_wf, 
itermMinus_wf, 
real_term_value_minus_lemma, 
rnexp_wf, 
istype-false, 
istype-le, 
real-vec-norm_wf, 
rnexp-positive, 
req_inversion, 
real-vec-norm-squared, 
rless_wf, 
req_wf, 
iff_weakening_uiff, 
rmul-assoc, 
req_transitivity, 
dot-product-linearity2, 
rmul_functionality, 
rmul_preserves_req, 
radd-preserves-req, 
rdiv_wf, 
rless-int, 
rinv_wf2, 
rmul-rinv, 
minus-one-mul-top, 
subtype_base_sq, 
int_subtype_base, 
nequal_wf, 
rsub_functionality, 
radd_functionality, 
int-rinv-cancel2, 
real-vec-add_functionality, 
squash_wf, 
true_wf, 
real_wf, 
subtype_rel_self, 
iff_weakening_equal, 
rmul-rinv3, 
efficient-exp-ext
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
isectElimination, 
hypothesis, 
independent_functionElimination, 
sqequalRule, 
universeIsType, 
inhabitedIsType, 
natural_numberEquality, 
applyEquality, 
lambdaEquality_alt, 
setElimination, 
rename, 
equalityTransitivity, 
equalitySymmetry, 
because_Cache, 
independent_isectElimination, 
productElimination, 
minusEquality, 
approximateComputation, 
int_eqEquality, 
isect_memberEquality_alt, 
voidElimination, 
dependent_set_memberEquality_alt, 
independent_pairFormation, 
equalityIsType1, 
inrFormation_alt, 
closedConclusion, 
imageMemberEquality, 
baseClosed, 
instantiate, 
cumulativity, 
intEquality, 
equalityIsType4, 
imageElimination, 
universeEquality
Latex:
\mforall{}n:\mBbbN{}.  \mforall{}a,b,c,a':\mBbbR{}\^{}n.    (a-b-a'  {}\mRightarrow{}  ab=a'b  {}\mRightarrow{}  ab=cb  {}\mRightarrow{}  c  \mneq{}  a  {}\mRightarrow{}  c  \mneq{}  a'  {}\mRightarrow{}  rv-pos-angle(n;a;b;c))
Date html generated:
2019_10_30-AM-08_48_29
Last ObjectModification:
2018_11_08-PM-02_13_53
Theory : reals
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