Nuprl Lemma : rational-truncate
∀q:ℚ. ∀e:{e:ℚ| 0 < e} .  (∃q':ℚ [(|q - q'| ≤ e)])
Proof
Definitions occuring in Statement : 
qabs: |r|, 
qle: r ≤ s, 
qless: r < s, 
qsub: r - s, 
rationals: ℚ, 
all: ∀x:A. B[x], 
sq_exists: ∃x:A [B[x]], 
set: {x:A| B[x]} , 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
sq_exists: ∃x:A [B[x]], 
member: t ∈ T, 
prop: ℙ, 
uall: ∀[x:A]. B[x], 
so_lambda: λ2x.t[x], 
subtype_rel: A ⊆r B, 
so_apply: x[s], 
implies: P ⇒ Q, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
uimplies: b supposing a, 
guard: {T}, 
iff: P ⇐⇒ Q, 
ifthenelse: if b then t else f fi , 
bfalse: ff, 
exists: ∃x:A. B[x], 
or: P ∨ Q, 
sq_type: SQType(T), 
bnot: ¬bb, 
assert: ↑b, 
false: False, 
squash: ↓T, 
true: True, 
pi1: fst(t), 
cand: A c∧ B, 
pi2: snd(t), 
nat_plus: ℕ+, 
int_nzero: ℤ-o, 
nequal: a ≠ b ∈ T , 
not: ¬A, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
top: Top, 
mk-rational: mk-rational(a;b), 
sq_stable: SqStable(P), 
rev_implies: P ⇐ Q, 
qsub: r - s
Lemmas referenced : 
set_wf, 
rationals_wf, 
qless_wf, 
int-subtype-rationals, 
q_less_wf, 
bool_wf, 
eqtt_to_assert, 
assert-q_less-eq, 
iff_weakening_equal, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
not_wf, 
squash_wf, 
true_wf, 
rational-truncate1, 
all_wf, 
sq_exists_wf, 
nat_plus_wf, 
qle_wf, 
qabs_wf, 
qsub_wf, 
qdiv_wf, 
subtype_rel_set, 
less_than_wf, 
int_nzero-rational, 
subtype_rel_sets, 
nequal_wf, 
nat_plus_properties, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformeq_wf, 
itermVar_wf, 
itermConstant_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_eq_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
equal-wf-base, 
int_subtype_base, 
qmul_wf, 
subtype_rel_transitivity, 
int_nzero_wf, 
mk-rational_wf, 
integer-part_wf, 
sq_stable_from_decidable, 
decidable__qle, 
qdiv-int-elim, 
fractional-part_wf, 
integer-fractional-parts, 
mon_assoc_q, 
qadd_ac_1_q, 
qadd_wf, 
qinverse_q, 
mon_ident_q, 
qless_complement_qorder, 
qabs-of-nonneg, 
qless_transitivity_2_qorder, 
qle_weakening_lt_qorder
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
dependent_set_memberFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesis, 
sqequalRule, 
lambdaEquality, 
natural_numberEquality, 
applyEquality, 
hypothesisEquality, 
setElimination, 
rename, 
because_Cache, 
unionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
independent_isectElimination, 
independent_functionElimination, 
dependent_pairFormation, 
promote_hyp, 
dependent_functionElimination, 
instantiate, 
cumulativity, 
voidElimination, 
imageElimination, 
universeEquality, 
imageMemberEquality, 
baseClosed, 
setEquality, 
productEquality, 
intEquality, 
applyLambdaEquality, 
int_eqEquality, 
isect_memberEquality, 
voidEquality, 
independent_pairFormation, 
computeAll, 
functionExtensionality, 
dependent_set_memberEquality, 
independent_pairEquality, 
minusEquality
Latex:
\mforall{}q:\mBbbQ{}.  \mforall{}e:\{e:\mBbbQ{}|  0  <  e\}  .    (\mexists{}q':\mBbbQ{}  [(|q  -  q'|  \mleq{}  e)])
Date html generated:
2018_05_22-AM-00_31_22
Last ObjectModification:
2017_07_26-PM-06_58_59
Theory : rationals
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