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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