Nuprl Lemma : rcos_wf1

∀[x:ℝ]. (rcos(x) ∈ {y:ℝ| cosine(x) = y} )


Proof




Definitions occuring in Statement :  rcos: rcos(x),  cosine: cosine(x),  req: x = y,  real: ℝ,  uall: ∀[x:A]. B[x],  member: t ∈ T,  set: {x:A| B[x]} 
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  all: ∀x:A. B[x],  so_lambda: λ2x.t[x],  rfun: I ⟶ℝ,  prop: ℙ,  so_apply: x[s],  implies: P ⇒ Q,  uimplies: b supposing a,  uiff: uiff(P;Q),  and: P ∧ Q,  rev_uimplies: rev_uimplies(P;Q),  nat: ℕ,  le: A ≤ B,  less_than': less_than'(a;b),  false: False,  not: ¬A,  rcos: rcos(x),  subtype_rel: A ⊆r B,  guard: {T},  squash: ↓T,  true: True,  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q
Lemmas referenced :  approx-arg_wf,  cosine_wf,  real_wf,  i-member_wf,  riiint_wf,  rminus_wf,  sine_wf,  req_functionality,  rminus_functionality,  sine_functionality,  req_weakening,  req_wf,  derivative-cosine,  false_wf,  le_wf,  subtype_rel_sets,  req_inversion,  rleq_wf,  squash_wf,  true_wf,  rabs-rminus,  int-to-real_wf,  iff_weakening_equal,  rabs-sine-rleq
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  extract_by_obid,  sqequalHypSubstitution,  dependent_functionElimination,  thin,  sqequalRule,  lambdaEquality,  isectElimination,  setElimination,  rename,  hypothesisEquality,  hypothesis,  setEquality,  because_Cache,  independent_functionElimination,  lambdaFormation,  independent_isectElimination,  productElimination,  dependent_set_memberEquality,  natural_numberEquality,  independent_pairFormation,  equalityTransitivity,  equalitySymmetry,  applyEquality,  axiomEquality,  imageElimination,  imageMemberEquality,  baseClosed,  universeEquality

Latex:
\mforall{}[x:\mBbbR{}].  (rcos(x)  \mmember{}  \{y:\mBbbR{}|  cosine(x)  =  y\}  )



Date html generated: 2017_01_09-AM-09_10_43
Last ObjectModification: 2016_11_25-PM-09_54_37

Theory : reals_2


Home Index