Nuprl Lemma : integer-nth-root-ext
∀n:ℕ+. ∀x:ℕ.  (∃r:ℕ [((r^n ≤ x) ∧ x < (r + 1)^n)])
Proof
Definitions occuring in Statement : 
exp: i^n
, 
nat_plus: ℕ+
, 
nat: ℕ
, 
less_than: a < b
, 
le: A ≤ B
, 
all: ∀x:A. B[x]
, 
sq_exists: ∃x:A [B[x]]
, 
and: P ∧ Q
, 
add: n + m
, 
natural_number: $n
Definitions unfolded in proof : 
member: t ∈ T
, 
so_apply: x[s1;s2]
, 
natrec: natrec, 
genrec: genrec, 
genrec-ap: genrec-ap, 
integer-nth-root, 
div_nat_induction, 
rem_bounds_1, 
decidable__lt, 
decidable__equal_int, 
decidable__squash, 
decidable__and, 
decidable__less_than', 
decidable__int_equal, 
decidable_functionality, 
squash_elim, 
sq_stable_from_decidable, 
any: any x
, 
iff_preserves_decidability, 
sq_stable__from_stable, 
stable__from_decidable, 
uall: ∀[x:A]. B[x]
, 
so_lambda: so_lambda(x,y,z,w.t[x; y; z; w])
, 
so_apply: x[s1;s2;s3;s4]
, 
so_lambda: λ2x.t[x]
, 
top: Top
, 
so_apply: x[s]
, 
uimplies: b supposing a
Lemmas referenced : 
integer-nth-root, 
lifting-strict-int_eq, 
istype-void, 
strict4-decide, 
lifting-strict-decide, 
lifting-strict-less, 
div_nat_induction, 
rem_bounds_1, 
decidable__lt, 
decidable__equal_int, 
decidable__squash, 
decidable__and, 
decidable__less_than', 
decidable__int_equal, 
decidable_functionality, 
squash_elim, 
sq_stable_from_decidable, 
iff_preserves_decidability, 
sq_stable__from_stable, 
stable__from_decidable
Rules used in proof : 
introduction, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
cut, 
instantiate, 
extract_by_obid, 
hypothesis, 
sqequalRule, 
thin, 
sqequalHypSubstitution, 
equalityTransitivity, 
equalitySymmetry, 
isectElimination, 
baseClosed, 
Error :isect_memberEquality_alt, 
voidElimination, 
independent_isectElimination
Latex:
\mforall{}n:\mBbbN{}\msupplus{}.  \mforall{}x:\mBbbN{}.    (\mexists{}r:\mBbbN{}  [((r\^{}n  \mleq{}  x)  \mwedge{}  x  <  (r  +  1)\^{}n)])
Date html generated:
2019_06_20-PM-02_33_42
Last ObjectModification:
2019_04_15-PM-10_31_53
Theory : num_thy_1
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