Nuprl Lemma : combinations-step
∀[n,m:ℕ].  (C(n;m) ~ if (n =z 0) then 1 else m * C(n - 1;m - 1) fi )
Proof
Definitions occuring in Statement : 
combinations: C(n;m)
, 
nat: ℕ
, 
ifthenelse: if b then t else f fi 
, 
eq_int: (i =z j)
, 
uall: ∀[x:A]. B[x]
, 
multiply: n * m
, 
subtract: n - m
, 
natural_number: $n
, 
sqequal: s ~ t
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
combinations: C(n;m)
, 
combinations_aux: combinations_aux(b;n;m)
, 
nat: ℕ
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
exists: ∃x:A. B[x]
, 
prop: ℙ
, 
or: P ∨ Q
, 
sq_type: SQType(T)
, 
guard: {T}
, 
bnot: ¬bb
, 
assert: ↑b
, 
false: False
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
not: ¬A
, 
ge: i ≥ j 
, 
int_upper: {i...}
, 
has-value: (a)↓
, 
decidable: Dec(P)
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
top: Top
Lemmas referenced : 
nat_wf, 
eq_int_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_eq_int, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
neg_assert_of_eq_int, 
int_upper_subtype_nat, 
false_wf, 
le_wf, 
nat_properties, 
nequal-le-implies, 
zero-add, 
value-type-has-value, 
int-value-type, 
int_subtype_base, 
subtract_wf, 
combinations_aux_linear, 
int_upper_properties, 
decidable__le, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermSubtract_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_subtract_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
decidable__equal_int, 
multiply-is-int-iff, 
intformeq_wf, 
itermMultiply_wf, 
int_formula_prop_eq_lemma, 
int_term_value_mul_lemma
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
hypothesis, 
sqequalAxiom, 
extract_by_obid, 
sqequalRule, 
sqequalHypSubstitution, 
isect_memberEquality, 
isectElimination, 
thin, 
hypothesisEquality, 
because_Cache, 
setElimination, 
rename, 
natural_numberEquality, 
lambdaFormation, 
unionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
independent_isectElimination, 
dependent_pairFormation, 
promote_hyp, 
dependent_functionElimination, 
instantiate, 
cumulativity, 
independent_functionElimination, 
voidElimination, 
hypothesis_subsumption, 
dependent_set_memberEquality, 
independent_pairFormation, 
callbyvalueReduce, 
intEquality, 
multiplyEquality, 
lambdaEquality, 
int_eqEquality, 
voidEquality, 
computeAll, 
pointwiseFunctionality, 
baseApply, 
closedConclusion, 
baseClosed
Latex:
\mforall{}[n,m:\mBbbN{}].    (C(n;m)  \msim{}  if  (n  =\msubz{}  0)  then  1  else  m  *  C(n  -  1;m  -  1)  fi  )
Date html generated:
2018_05_21-PM-08_09_16
Last ObjectModification:
2017_07_26-PM-05_44_57
Theory : general
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