Nuprl Lemma : tsqrt-unique
∀[n,x:ℕ].  (((t(x) ≤ n) ∧ n < t(x + 1)) 
⇒ (x = tsqrt(n) ∈ ℤ))
Proof
Definitions occuring in Statement : 
tsqrt: tsqrt(n)
, 
triangular-num: t(n)
, 
nat: ℕ
, 
less_than: a < b
, 
uall: ∀[x:A]. B[x]
, 
le: A ≤ B
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
add: n + m
, 
natural_number: $n
, 
int: ℤ
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
nat: ℕ
, 
ge: i ≥ j 
, 
all: ∀x:A. B[x]
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
uimplies: b supposing a
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
not: ¬A
, 
top: Top
, 
less_than: a < b
, 
squash: ↓T
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
guard: {T}
Lemmas referenced : 
tsqrt-property, 
le_wf, 
triangular-num_wf, 
less_than_wf, 
nat_properties, 
decidable__le, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermAdd_wf, 
itermVar_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_add_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
nat_wf, 
decidable__lt, 
tsqrt_wf, 
triangular-num-le, 
intformless_wf, 
int_formula_prop_less_lemma, 
decidable__equal_int, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
add_nat_wf, 
false_wf, 
equal_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
lambdaFormation, 
sqequalHypSubstitution, 
productElimination, 
thin, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
productEquality, 
applyEquality, 
because_Cache, 
sqequalRule, 
setElimination, 
rename, 
dependent_set_memberEquality, 
addEquality, 
natural_numberEquality, 
dependent_functionElimination, 
unionElimination, 
independent_isectElimination, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
computeAll, 
axiomEquality, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
applyLambdaEquality, 
independent_functionElimination
Latex:
\mforall{}[n,x:\mBbbN{}].    (((t(x)  \mleq{}  n)  \mwedge{}  n  <  t(x  +  1))  {}\mRightarrow{}  (x  =  tsqrt(n)))
Date html generated:
2019_06_20-PM-02_38_45
Last ObjectModification:
2019_06_12-PM-00_27_02
Theory : num_thy_1
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