Nuprl Lemma : vars-of-subst_wf
∀[opr:Type]. ∀[s:(varname() × term(opr)) List].  (vars-of-subst(s) ∈ {v:varname()| ¬(v = nullvar() ∈ varname())}  List)
Proof
Definitions occuring in Statement : 
vars-of-subst: vars-of-subst(s), 
term: term(opr), 
nullvar: nullvar(), 
varname: varname(), 
list: T List, 
uall: ∀[x:A]. B[x], 
not: ¬A, 
member: t ∈ T, 
set: {x:A| B[x]} , 
product: x:A × B[x], 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
vars-of-subst: vars-of-subst(s), 
prop: ℙ, 
subtype_rel: A ⊆r B, 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
ifthenelse: if b then t else f fi , 
bfalse: ff, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
uimplies: b supposing a, 
exists: ∃x:A. B[x], 
or: P ∨ Q, 
sq_type: SQType(T), 
guard: {T}, 
bnot: ¬bb, 
assert: ↑b, 
false: False, 
not: ¬A, 
rev_implies: P ⇐ Q, 
iff: P ⇐⇒ Q
Lemmas referenced : 
l-union-list_wf, 
varname_wf, 
not_wf, 
equal_wf, 
nullvar_wf, 
var-deq_wf, 
map_wf, 
term_wf, 
list_wf, 
eq_var_wf, 
free-vars_wf, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
assert-bnot, 
iff_weakening_uiff, 
assert_wf, 
equal-wf-T-base, 
assert-eq_var, 
insert_wf, 
istype-void, 
istype-universe
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
sqequalRule, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
closedConclusion, 
setEquality, 
hypothesis, 
hypothesisEquality, 
applyEquality, 
because_Cache, 
productEquality, 
lambdaEquality_alt, 
productElimination, 
inhabitedIsType, 
lambdaFormation_alt, 
unionElimination, 
equalityElimination, 
independent_isectElimination, 
equalityTransitivity, 
equalitySymmetry, 
dependent_pairFormation_alt, 
equalityIstype, 
promote_hyp, 
dependent_functionElimination, 
instantiate, 
cumulativity, 
independent_functionElimination, 
voidElimination, 
dependent_set_memberEquality_alt, 
functionIsType, 
productIsType, 
universeIsType, 
axiomEquality, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
universeEquality
Latex:
\mforall{}[opr:Type].  \mforall{}[s:(varname()  \mtimes{}  term(opr))  List].
    (vars-of-subst(s)  \mmember{}  \{v:varname()|  \mneg{}(v  =  nullvar())\}    List)
Date html generated:
2020_05_19-PM-09_57_42
Last ObjectModification:
2020_03_09-PM-04_09_56
Theory : terms
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