Nuprl Lemma : set_leq_iff_lt_or_eq

∀s:POSet{i}. ∀a,b:|s|.  (a ≤ b ⇐⇒ (a <s b) ∨ (a = b ∈ |s|))


Proof




Definitions occuring in Statement :  poset: POSet{i},  set_lt: a <p b,  set_leq: a ≤ b,  set_car: |p|,  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  or: P ∨ Q,  equal: s = t ∈ T
Definitions unfolded in proof :  all: ∀x:A. B[x],  member: t ∈ T,  uall: ∀[x:A]. B[x],  poset: POSet{i},  qoset: QOSet,  dset: DSet,  ab_binrel: x,y:T. E[x; y],  so_lambda: λ2x y.t[x; y],  so_apply: x[s1;s2],  prop: ℙ,  iff: P ⇐⇒ Q,  and: P ∧ Q,  implies: P ⇒ Q,  rev_implies: P ⇐ Q,  decidable: Dec(P),  or: P ∨ Q,  set_lt: a <p b,  set_blt: a <b b,  infix_ap: x f y,  cand: A c∧ B,  not: ¬A,  guard: {T},  uimplies: b supposing a,  false: False,  uiff: uiff(P;Q)
Lemmas referenced :  set_car_wf,  poset_wf,  poset_properties,  qoset_wf,  uanti_sym_wf,  set_leq_wf,  qoset_properties,  dset_wf,  upreorder_wf,  dset_properties,  poset_sig_wf,  eqfun_p_wf,  set_eq_wf,  or_wf,  set_lt_wf,  equal_wf,  decidable__dset_eq,  assert_wf,  band_wf,  set_le_wf,  bnot_wf,  and_wf,  not_wf,  set_leq_antisymmetry,  iff_transitivity,  iff_weakening_uiff,  assert_of_band,  assert_of_set_leq,  assert_of_bnot,  set_leq_weakening_lt,  set_leq_weakening_eq
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  cut,  lemma_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  setElimination,  rename,  hypothesisEquality,  hypothesis,  sqequalRule,  applyEquality,  lambdaEquality,  setEquality,  cumulativity,  equalityTransitivity,  equalitySymmetry,  independent_pairFormation,  dependent_functionElimination,  unionElimination,  inrFormation,  inlFormation,  because_Cache,  independent_functionElimination,  independent_isectElimination,  voidElimination,  productElimination,  impliesFunctionality

Latex:
\mforall{}s:POSet\{i\}.  \mforall{}a,b:|s|.    (a  \mleq{}  b  \mLeftarrow{}{}\mRightarrow{}  (a  <s  b)  \mvee{}  (a  =  b))



Date html generated: 2016_05_15-PM-00_05_12
Last ObjectModification: 2015_12_26-PM-11_28_28

Theory : sets_1


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