Nuprl Lemma : ratsign_wf

[x:ℤ × ℕ+]. (ratsign(x) ∈ {-1..2-})


Proof




Definitions occuring in Statement :  ratsign: ratsign(x) int_seg: {i..j-} nat_plus: + uall: [x:A]. B[x] member: t ∈ T product: x:A × B[x] minus: -n natural_number: $n int:
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T ratsign: ratsign(x) has-value: (a)↓ uimplies: supposing a top: Top pi1: fst(t) all: x:A. B[x] implies:  Q bool: 𝔹 unit: Unit it: btrue: tt ifthenelse: if then else fi  uiff: uiff(P;Q) and: P ∧ Q int_seg: {i..j-} lelt: i ≤ j < k decidable: Dec(P) or: P ∨ Q not: ¬A satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] prop: false: False bfalse: ff sq_type: SQType(T) guard: {T} bnot: ¬bb assert: b rev_implies:  Q iff: ⇐⇒ Q
Lemmas referenced :  value-type-has-value int-value-type pi1_wf_top istype-void lt_int_wf eqtt_to_assert assert_of_lt_int decidable__le full-omega-unsat intformnot_wf intformle_wf itermConstant_wf istype-int int_formula_prop_not_lemma int_formula_prop_le_lemma int_term_value_constant_lemma int_formula_prop_wf decidable__lt intformless_wf int_formula_prop_less_lemma istype-le istype-less_than eqff_to_assert bool_cases_sqequal subtype_base_sq bool_wf bool_subtype_base assert-bnot iff_weakening_uiff assert_wf less_than_wf nat_plus_wf
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation_alt introduction cut sqequalRule callbyvalueReduce extract_by_obid sqequalHypSubstitution isectElimination thin intEquality independent_isectElimination hypothesis productElimination independent_pairEquality hypothesisEquality isect_memberEquality_alt voidElimination closedConclusion natural_numberEquality because_Cache inhabitedIsType lambdaFormation_alt unionElimination equalityElimination dependent_set_memberEquality_alt minusEquality independent_pairFormation dependent_functionElimination approximateComputation independent_functionElimination dependent_pairFormation_alt lambdaEquality_alt universeIsType productIsType equalityTransitivity equalitySymmetry equalityIstype promote_hyp instantiate cumulativity axiomEquality

Latex:
\mforall{}[x:\mBbbZ{}  \mtimes{}  \mBbbN{}\msupplus{}].  (ratsign(x)  \mmember{}  \{-1..2\msupminus{}\})



Date html generated: 2019_10_30-AM-09_35_28
Last ObjectModification: 2019_01_17-AM-10_24_53

Theory : reals


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