Nuprl Lemma : tag-by-subtype-tag-case
∀[T,S:Type].  ∀z,x:Atom.  (z×T ⊆r x:S 
⇐⇒ (¬↑z =a x) ∨ (T ⊆r S))
Proof
Definitions occuring in Statement : 
tag-by: z×T
, 
tag-case: z:T
, 
assert: ↑b
, 
eq_atom: x =a y
, 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
not: ¬A
, 
or: P ∨ Q
, 
atom: Atom
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
assert: ↑b
, 
ifthenelse: if b then t else f fi 
, 
iff: P 
⇐⇒ Q
, 
or: P ∨ Q
, 
subtype_rel: A ⊆r B
, 
rev_implies: P 
⇐ Q
, 
not: ¬A
, 
true: True
, 
false: False
, 
bfalse: ff
, 
exists: ∃x:A. B[x]
, 
sq_type: SQType(T)
, 
guard: {T}
, 
bnot: ¬bb
, 
tag-by: z×T
, 
tag-case: z:T
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
nequal: a ≠ b ∈ T 
, 
top: Top
, 
pi2: snd(t)
, 
pi1: fst(t)
Lemmas referenced : 
eq_atom_wf, 
eqtt_to_assert, 
assert_of_eq_atom, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
assert-bnot, 
neg_assert_of_eq_atom, 
istype-void, 
subtype_rel_wf, 
tag-by_wf, 
tag-case_wf, 
subtype_rel_product, 
equal-wf-base, 
atom_subtype_base, 
ifthenelse_wf, 
top_wf, 
istype-atom, 
istype-universe, 
subtype_rel-equal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
inhabitedIsType, 
unionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
independent_isectElimination, 
sqequalRule, 
independent_pairFormation, 
inrFormation_alt, 
lambdaEquality_alt, 
universeIsType, 
because_Cache, 
independent_functionElimination, 
natural_numberEquality, 
voidElimination, 
axiomEquality, 
dependent_pairFormation_alt, 
equalityIstype, 
promote_hyp, 
dependent_functionElimination, 
instantiate, 
cumulativity, 
inlFormation_alt, 
setEquality, 
atomEquality, 
applyEquality, 
setIsType, 
universeEquality, 
setElimination, 
rename, 
isect_memberEquality_alt, 
unionIsType, 
functionIsType, 
dependent_set_memberEquality_alt, 
productIsType, 
applyLambdaEquality, 
sqequalBase, 
independent_pairEquality
Latex:
\mforall{}[T,S:Type].    \mforall{}z,x:Atom.    (z\mtimes{}T  \msubseteq{}r  x:S  \mLeftarrow{}{}\mRightarrow{}  (\mneg{}\muparrow{}z  =a  x)  \mvee{}  (T  \msubseteq{}r  S))
Date html generated:
2019_10_15-AM-11_29_46
Last ObjectModification:
2019_06_25-PM-01_21_26
Theory : general
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