Nuprl Lemma : count-combinations
∀n,m:ℕ.  Combination(n;ℕm) ~ ℕC(n;m)
This theorem is one of freek's list of 100 theorems
Proof
Definitions occuring in Statement : 
combinations: C(n;m)
, 
combination: Combination(n;T)
, 
equipollent: A ~ B
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
all: ∀x:A. B[x]
, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
nat: ℕ
, 
ge: i ≥ j 
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
uimplies: b supposing a
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
top: Top
, 
and: P ∧ Q
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
eq_int: (i =z j)
, 
subtract: n - m
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
equipollent: A ~ B
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
less_than: a < b
, 
squash: ↓T
, 
true: True
, 
biject: Bij(A;B;f)
, 
inject: Inj(A;B;f)
, 
surject: Surj(A;B;f)
, 
combination: Combination(n;T)
, 
cand: A c∧ B
, 
subtype_rel: A ⊆r B
, 
cons: [a / b]
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
sq_type: SQType(T)
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
uiff: uiff(P;Q)
, 
bfalse: ff
, 
rev_implies: P 
⇐ Q
, 
nat_plus: ℕ+
, 
pi1: fst(t)
, 
pi2: snd(t)
, 
l_member: (x ∈ l)
Lemmas referenced : 
nat_wf, 
equipollent_wf, 
combination_wf, 
int_seg_wf, 
subtract_wf, 
combinations_wf_int, 
nat_properties, 
decidable__le, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermSubtract_wf, 
itermVar_wf, 
intformless_wf, 
istype-int, 
int_formula_prop_and_lemma, 
istype-void, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_subtract_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
le_wf, 
less_than_wf, 
primrec-wf2, 
all_wf, 
combinations-step, 
istype-false, 
biject_wf, 
list-cases, 
length_of_nil_lemma, 
nil_wf, 
no_repeats_wf, 
length_wf_nat, 
set_subtype_base, 
int_subtype_base, 
product_subtype_list, 
length_of_cons_lemma, 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
subtype_rel_self, 
iff_weakening_equal, 
non_neg_length, 
int_seg_properties, 
intformeq_wf, 
itermAdd_wf, 
int_formula_prop_eq_lemma, 
int_term_value_add_lemma, 
subtype_rel-equal, 
base_wf, 
no_repeats_nil, 
length_nil, 
list_subtype_base, 
lelt_wf, 
decidable__equal_int, 
subtype_base_sq, 
eq_int_wf, 
equal-wf-base, 
bool_wf, 
assert_wf, 
bnot_wf, 
not_wf, 
itermMultiply_wf, 
int_term_value_mul_lemma, 
uiff_transitivity, 
eqtt_to_assert, 
assert_of_eq_int, 
iff_transitivity, 
iff_weakening_uiff, 
eqff_to_assert, 
assert_of_bnot, 
equipollent-zero, 
combination-decomp, 
subtype_rel_set, 
list_wf, 
equal-wf-base-T, 
equal-wf-T-base, 
subtype_rel_list, 
product_subtype_base, 
pi1_wf_top, 
reduce_tl_nil_lemma, 
reduce_tl_cons_lemma, 
reduce_hd_cons_lemma, 
cons_wf, 
no_repeats_cons, 
no_repeats-settype, 
l_member_wf, 
select_wf, 
equipollent_functionality_wrt_equipollent, 
equipollent_weakening_ext-eq, 
ext-eq_weakening, 
equipollent-subtract-one, 
id-biject, 
product_functionality_wrt_equipollent_dependent, 
equipollent_same, 
combination_functionality, 
equipollent-multiply, 
combinations_wf, 
product_functionality_wrt_equipollent_right
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
thin, 
universeIsType, 
because_Cache, 
rename, 
setElimination, 
sqequalRule, 
functionIsType, 
introduction, 
extract_by_obid, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
natural_numberEquality, 
hypothesisEquality, 
dependent_set_memberEquality_alt, 
dependent_functionElimination, 
unionElimination, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
int_eqEquality, 
isect_memberEquality_alt, 
voidElimination, 
independent_pairFormation, 
setIsType, 
inhabitedIsType, 
imageMemberEquality, 
baseClosed, 
productIsType, 
equalityIsType4, 
productElimination, 
equalityTransitivity, 
equalitySymmetry, 
applyEquality, 
intEquality, 
promote_hyp, 
hypothesis_subsumption, 
imageElimination, 
universeEquality, 
instantiate, 
applyLambdaEquality, 
baseApply, 
closedConclusion, 
cumulativity, 
equalityElimination, 
equalityIsType1, 
dependent_pairEquality_alt, 
setEquality, 
productEquality, 
independent_pairEquality, 
multiplyEquality
Latex:
\mforall{}n,m:\mBbbN{}.    Combination(n;\mBbbN{}m)  \msim{}  \mBbbN{}C(n;m)
Date html generated:
2019_10_15-AM-11_16_03
Last ObjectModification:
2018_10_09-PM-02_12_24
Theory : general
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