Nuprl Lemma : fact_wf
∀[n:ℕ]. ((n)! ∈ ℕ+)
Proof
Definitions occuring in Statement : 
fact: (n)!
, 
nat_plus: ℕ+
, 
nat: ℕ
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
nat: ℕ
, 
implies: P 
⇒ Q
, 
false: False
, 
ge: i ≥ j 
, 
uimplies: b supposing a
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
not: ¬A
, 
all: ∀x:A. B[x]
, 
top: Top
, 
and: P ∧ Q
, 
prop: ℙ
, 
eq_int: (i =z j)
, 
subtract: n - m
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
nat_plus: ℕ+
, 
less_than: a < b
, 
squash: ↓T
, 
less_than': less_than'(a;b)
, 
true: True
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
uiff: uiff(P;Q)
, 
bfalse: ff
, 
sq_type: SQType(T)
, 
guard: {T}
, 
bnot: ¬bb
, 
assert: ↑b
Lemmas referenced : 
nat_wf, 
mul_nat_plus, 
neg_assert_of_eq_int, 
assert-bnot, 
bool_subtype_base, 
subtype_base_sq, 
bool_cases_sqequal, 
equal_wf, 
eqff_to_assert, 
assert_of_eq_int, 
eqtt_to_assert, 
bool_wf, 
eq_int_wf, 
int_term_value_subtract_lemma, 
int_formula_prop_not_lemma, 
itermSubtract_wf, 
intformnot_wf, 
subtract_wf, 
decidable__le, 
fact_unroll, 
less_than_wf, 
ge_wf, 
int_formula_prop_wf, 
int_formula_prop_less_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_le_lemma, 
int_formula_prop_and_lemma, 
intformless_wf, 
itermVar_wf, 
itermConstant_wf, 
intformle_wf, 
intformand_wf, 
satisfiable-full-omega-tt, 
nat_properties
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
intWeakElimination, 
lambdaFormation, 
natural_numberEquality, 
independent_isectElimination, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
sqequalRule, 
independent_pairFormation, 
computeAll, 
independent_functionElimination, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
dependent_set_memberEquality, 
imageMemberEquality, 
baseClosed, 
unionElimination, 
equalityElimination, 
productElimination, 
because_Cache, 
promote_hyp, 
instantiate, 
cumulativity, 
equalityEquality
Latex:
\mforall{}[n:\mBbbN{}].  ((n)!  \mmember{}  \mBbbN{}\msupplus{})
Date html generated:
2016_05_15-PM-04_05_06
Last ObjectModification:
2016_01_16-AM-11_01_28
Theory : general
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