Nuprl Lemma : rsqrt-unique
∀[x,s:{x:ℝ| r0 ≤ x} ].  s = rsqrt(x) supposing (s * s) = x
Proof
Definitions occuring in Statement : 
rsqrt: rsqrt(x)
, 
rleq: x ≤ y
, 
req: x = y
, 
rmul: a * b
, 
int-to-real: r(n)
, 
real: ℝ
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
set: {x:A| B[x]} 
, 
natural_number: $n
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
and: P ∧ Q
, 
sq_stable: SqStable(P)
, 
implies: P 
⇒ Q
, 
cand: A c∧ B
, 
all: ∀x:A. B[x]
, 
squash: ↓T
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
uiff: uiff(P;Q)
, 
not: ¬A
, 
rev_uimplies: rev_uimplies(P;Q)
, 
rsub: x - y
, 
rneq: x ≠ y
, 
or: P ∨ Q
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
guard: {T}
, 
rless: x < y
, 
sq_exists: ∃x:{A| B[x]}
, 
false: False
, 
nat_plus: ℕ+
, 
less_than: a < b
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
top: Top
, 
true: True
Lemmas referenced : 
sq_stable__req, 
rsqrt_wf, 
rleq_wf, 
int-to-real_wf, 
real_wf, 
req_wf, 
rmul_wf, 
rsqrt_squared, 
rsqrt_nonneg, 
equal_wf, 
req_witness, 
set_wf, 
req-iff-not-rneq, 
rneq_wf, 
rsub_wf, 
radd_wf, 
rminus_wf, 
req_weakening, 
req_functionality, 
rsub_functionality, 
radd-rminus-both, 
req_inversion, 
uiff_transitivity, 
req_transitivity, 
rmul-distrib, 
radd_functionality, 
rmul_over_rminus, 
rmul_comm, 
radd-assoc, 
radd-rminus-assoc, 
radd-preserves-rless, 
rless_wf, 
rless_functionality, 
radd-zero-both, 
radd-ac, 
radd_comm, 
rmul-neq-zero, 
nat_plus_properties, 
satisfiable-full-omega-tt, 
intformless_wf, 
itermAdd_wf, 
itermVar_wf, 
itermConstant_wf, 
int_formula_prop_less_lemma, 
int_term_value_add_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_wf, 
rneq_functionality, 
radd-preserves-req, 
rleq_transitivity, 
rleq_weakening, 
radd-preserves-rleq, 
rleq_antisymmetry, 
rleq_functionality, 
rminus-as-rmul, 
rmul-identity1, 
rmul-distrib2, 
rmul_functionality, 
radd-int, 
rmul-zero-both, 
squash_wf, 
true_wf, 
rminus-int, 
iff_weakening_equal, 
minus-zero, 
rminus_functionality, 
rless_transitivity1, 
rless_irreflexivity
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
setElimination, 
thin, 
rename, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
dependent_set_memberEquality, 
hypothesis, 
natural_numberEquality, 
applyEquality, 
lambdaEquality, 
setEquality, 
productEquality, 
sqequalRule, 
independent_functionElimination, 
independent_pairFormation, 
because_Cache, 
lambdaFormation, 
productElimination, 
equalityTransitivity, 
equalitySymmetry, 
dependent_functionElimination, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
isect_memberEquality, 
independent_isectElimination, 
unionElimination, 
inlFormation, 
inrFormation, 
addLevel, 
levelHypothesis, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
voidElimination, 
voidEquality, 
computeAll, 
minusEquality, 
addEquality, 
universeEquality
Latex:
\mforall{}[x,s:\{x:\mBbbR{}|  r0  \mleq{}  x\}  ].    s  =  rsqrt(x)  supposing  (s  *  s)  =  x
Date html generated:
2017_10_03-AM-10_43_04
Last ObjectModification:
2017_07_28-AM-08_18_16
Theory : reals
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