Nuprl Lemma : equipollent-multiply
∀a,b:ℕ.  ℕa × ℕb ~ ℕa * b
Proof
Definitions occuring in Statement : 
equipollent: A ~ B
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
all: ∀x:A. B[x]
, 
product: x:A × B[x]
, 
multiply: n * m
, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
equipollent: A ~ B
, 
exists: ∃x:A. B[x]
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
lelt: i ≤ j < k
, 
le: A ≤ B
, 
less_than: a < b
, 
squash: ↓T
, 
prop: ℙ
, 
top: Top
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
or: P ∨ Q
, 
decidable: Dec(P)
, 
ge: i ≥ j 
, 
guard: {T}
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
false: False
, 
less_than': less_than'(a;b)
, 
subtype_rel: A ⊆r B
, 
biject: Bij(A;B;f)
, 
inject: Inj(A;B;f)
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
surject: Surj(A;B;f)
, 
nat_plus: ℕ+
, 
div_nrel: Div(a;n;q)
, 
sq_type: SQType(T)
, 
int_nzero: ℤ-o
, 
nequal: a ≠ b ∈ T 
, 
subtract: n - m
, 
true: True
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
Lemmas referenced : 
add-member-int_seg1, 
istype-le, 
subtract_wf, 
istype-less_than, 
int_seg_wf, 
biject_wf, 
istype-nat, 
int_term_value_mul_lemma, 
itermMultiply_wf, 
int_formula_prop_wf, 
int_formula_prop_less_lemma, 
int_term_value_constant_lemma, 
int_term_value_subtract_lemma, 
int_term_value_var_lemma, 
int_formula_prop_le_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_and_lemma, 
istype-int, 
intformless_wf, 
itermConstant_wf, 
itermSubtract_wf, 
itermVar_wf, 
intformle_wf, 
intformnot_wf, 
intformand_wf, 
full-omega-unsat, 
decidable__le, 
nat_properties, 
int_seg_properties, 
mul_preserves_le, 
istype-void, 
int_seg_subtype_nat, 
mul_bounds_1a, 
decidable__lt, 
set_subtype_base, 
le_wf, 
int_subtype_base, 
product_subtype_base, 
lelt_wf, 
div_unique, 
istype-false, 
int_term_value_add_lemma, 
itermAdd_wf, 
int_formula_prop_eq_lemma, 
intformeq_wf, 
less_than_wf, 
decidable__equal_int, 
subtype_base_sq, 
remainder_wfa, 
nequal_wf, 
rem_bounds_1, 
minus-zero, 
minus-add, 
add-commutes, 
condition-implies-le, 
le-add-cancel, 
zero-add, 
add-zero, 
add-associates, 
add_functionality_wrt_le, 
not-equal-2, 
not-lt-2, 
div_rem_sum, 
div_bounds_1, 
false_wf, 
multiply-is-int-iff, 
add-is-int-iff
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :lambdaFormation_alt, 
Error :dependent_pairFormation_alt, 
Error :lambdaEquality_alt, 
productElimination, 
thin, 
sqequalRule, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
multiplyEquality, 
setElimination, 
rename, 
hypothesisEquality, 
hypothesis, 
closedConclusion, 
natural_numberEquality, 
because_Cache, 
independent_isectElimination, 
Error :dependent_set_memberEquality_alt, 
independent_pairFormation, 
Error :productIsType, 
imageElimination, 
Error :universeIsType, 
productEquality, 
Error :inhabitedIsType, 
voidElimination, 
Error :isect_memberEquality_alt, 
int_eqEquality, 
independent_functionElimination, 
approximateComputation, 
unionElimination, 
dependent_functionElimination, 
applyEquality, 
Error :equalityIstype, 
baseApply, 
baseClosed, 
intEquality, 
sqequalBase, 
equalitySymmetry, 
equalityTransitivity, 
applyLambdaEquality, 
addEquality, 
independent_pairEquality, 
cumulativity, 
instantiate, 
minusEquality, 
divideEquality, 
promote_hyp, 
pointwiseFunctionality
Latex:
\mforall{}a,b:\mBbbN{}.    \mBbbN{}a  \mtimes{}  \mBbbN{}b  \msim{}  \mBbbN{}a  *  b
Date html generated:
2019_06_20-PM-02_17_08
Last ObjectModification:
2019_06_19-PM-06_34_45
Theory : equipollence!!cardinality!
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