Nuprl Lemma : biject-quotient
∀A,B:Type. ∀f:A ⟶ B. ∀R:B ⟶ B ⟶ ℙ.
  (Bij(A;B;f) 
⇒ EquivRel(B;x,y.x R y) 
⇒ Bij(x,y:A//(x R_f y);x,y:B//(x R y);quo-lift(f)))
Proof
Definitions occuring in Statement : 
quo-lift: quo-lift(f)
, 
preima_of_rel: R_f
, 
equiv_rel: EquivRel(T;x,y.E[x; y])
, 
biject: Bij(A;B;f)
, 
quotient: x,y:A//B[x; y]
, 
prop: ℙ
, 
infix_ap: x f y
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
biject: Bij(A;B;f)
, 
and: P ∧ Q
, 
cand: A c∧ B
, 
inject: Inj(A;B;f)
, 
uall: ∀[x:A]. B[x]
, 
so_lambda: λ2x y.t[x; y]
, 
infix_ap: x f y
, 
so_apply: x[s1;s2]
, 
uimplies: b supposing a
, 
surject: Surj(A;B;f)
, 
prop: ℙ
, 
quotient: x,y:A//B[x; y]
, 
preima_of_rel: R_f
, 
subtype_rel: A ⊆r B
, 
quo-lift: quo-lift(f)
, 
equiv_rel: EquivRel(T;x,y.E[x; y])
, 
trans: Trans(T;x,y.E[x; y])
, 
exists: ∃x:A. B[x]
, 
pi1: fst(t)
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
, 
guard: {T}
Lemmas referenced : 
preima_of_equiv_rel, 
quo-lift_wf, 
quotient_wf, 
preima_of_rel_wf, 
equiv_rel_wf, 
biject_wf, 
istype-universe, 
infix_ap_wf, 
subtype_rel_self, 
quotient-member-eq, 
iff_weakening_equal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
independent_functionElimination, 
hypothesis, 
because_Cache, 
productElimination, 
Error :equalityIstype, 
Error :universeIsType, 
isectElimination, 
sqequalRule, 
Error :lambdaEquality_alt, 
applyEquality, 
Error :inhabitedIsType, 
independent_isectElimination, 
independent_pairFormation, 
Error :functionIsType, 
universeEquality, 
instantiate, 
pointwiseFunctionalityForEquality, 
cumulativity, 
pertypeElimination, 
Error :productIsType, 
sqequalBase, 
equalitySymmetry, 
equalityTransitivity, 
Error :equalityIsType1, 
promote_hyp, 
rename, 
Error :dependent_pairFormation_alt, 
functionExtensionality, 
Error :equalityIsType4
Latex:
\mforall{}A,B:Type.  \mforall{}f:A  {}\mrightarrow{}  B.  \mforall{}R:B  {}\mrightarrow{}  B  {}\mrightarrow{}  \mBbbP{}.
    (Bij(A;B;f)  {}\mRightarrow{}  EquivRel(B;x,y.x  R  y)  {}\mRightarrow{}  Bij(x,y:A//(x  R\_f  y);x,y:B//(x  R  y);quo-lift(f)))
Date html generated:
2019_06_20-PM-00_33_19
Last ObjectModification:
2018_11_24-AM-09_34_34
Theory : quot_1
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