Nuprl Lemma : real-vec-dist-equal-iff
∀[n:ℕ]. ∀[x,y,a,b:ℝ^n].  uiff(d(x;y) = d(a;b);x - y⋅x - y = a - b⋅a - b)
Proof
Definitions occuring in Statement : 
real-vec-dist: d(x;y), 
dot-product: x⋅y, 
real-vec-sub: X - Y, 
real-vec: ℝ^n, 
req: x = y, 
nat: ℕ, 
uiff: uiff(P;Q), 
uall: ∀[x:A]. B[x]
Definitions unfolded in proof : 
real-vec-dist: d(x;y), 
real-vec-norm: ||x||, 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
uimplies: b supposing a, 
prop: ℙ, 
subtype_rel: A ⊆r B, 
rev_uimplies: rev_uimplies(P;Q), 
guard: {T}
Lemmas referenced : 
dot-product-nonneg, 
real-vec-sub_wf, 
dot-product_wf, 
real_wf, 
req_witness, 
req_wf, 
rsqrt_wf, 
rleq_wf, 
int-to-real_wf, 
rmul_wf, 
req_functionality, 
rsqrt_functionality, 
req_weakening, 
equal_wf, 
real-vec-dist_wf, 
real-vec_wf, 
nat_wf, 
rsqrt_squared, 
req_inversion, 
req_transitivity, 
rmul_functionality
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
lambdaFormation, 
because_Cache, 
independent_pairFormation, 
isect_memberFormation, 
independent_functionElimination, 
dependent_set_memberEquality, 
natural_numberEquality, 
applyEquality, 
lambdaEquality, 
setElimination, 
rename, 
setEquality, 
productEquality, 
sqequalRule, 
independent_isectElimination, 
productElimination, 
equalityTransitivity, 
equalitySymmetry, 
dependent_functionElimination, 
independent_pairEquality, 
isect_memberEquality
Latex:
\mforall{}[n:\mBbbN{}].  \mforall{}[x,y,a,b:\mBbbR{}\^{}n].    uiff(d(x;y)  =  d(a;b);x  -  y\mcdot{}x  -  y  =  a  -  b\mcdot{}a  -  b)
 Date html generated: 
2017_10_03-AM-10_56_04
 Last ObjectModification: 
2017_07_28-AM-08_21_28
Theory : reals
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