Nuprl Lemma : mk-groupoid_wf
∀[C:SmallCategory]. ∀[inv:x:cat-ob(C) ⟶ y:cat-ob(C) ⟶ (cat-arrow(C) x y) ⟶ (cat-arrow(C) y x)].
  Groupoid(C;
           inv(x,y,f) = inv[x;y;f]) ∈ Groupoid 
  supposing ∀x,y:cat-ob(C). ∀f:cat-arrow(C) x y.
              (((cat-comp(C) x y x f inv[x;y;f]) = (cat-id(C) x) ∈ (cat-arrow(C) x x))
              ∧ ((cat-comp(C) y x y inv[x;y;f] f) = (cat-id(C) y) ∈ (cat-arrow(C) y y)))
Proof
Definitions occuring in Statement : 
mk-groupoid: mk-groupoid, 
groupoid: Groupoid
, 
cat-comp: cat-comp(C)
, 
cat-id: cat-id(C)
, 
cat-arrow: cat-arrow(C)
, 
cat-ob: cat-ob(C)
, 
small-category: SmallCategory
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s1;s2;s3]
, 
all: ∀x:A. B[x]
, 
and: P ∧ Q
, 
member: t ∈ T
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
mk-groupoid: mk-groupoid, 
groupoid: Groupoid
, 
so_apply: x[s1;s2;s3]
, 
so_lambda: λ2x.t[x]
, 
prop: ℙ
, 
and: P ∧ Q
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
Lemmas referenced : 
cat-ob_wf, 
cat-arrow_wf, 
all_wf, 
equal_wf, 
cat-comp_wf, 
cat-id_wf, 
small-category_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalRule, 
dependent_pairEquality, 
hypothesisEquality, 
dependent_set_memberEquality, 
lambdaEquality, 
applyEquality, 
functionExtensionality, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesis, 
because_Cache, 
productEquality, 
setEquality, 
functionEquality, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
isect_memberEquality
Latex:
\mforall{}[C:SmallCategory].  \mforall{}[inv:x:cat-ob(C)  {}\mrightarrow{}  y:cat-ob(C)  {}\mrightarrow{}  (cat-arrow(C)  x  y)  {}\mrightarrow{}  (cat-arrow(C)  y  x)].
    Groupoid(C;
                      inv(x,y,f)  =  inv[x;y;f])  \mmember{}  Groupoid 
    supposing  \mforall{}x,y:cat-ob(C).  \mforall{}f:cat-arrow(C)  x  y.
                            (((cat-comp(C)  x  y  x  f  inv[x;y;f])  =  (cat-id(C)  x))
                            \mwedge{}  ((cat-comp(C)  y  x  y  inv[x;y;f]  f)  =  (cat-id(C)  y)))
Date html generated:
2020_05_20-AM-07_55_21
Last ObjectModification:
2017_07_28-AM-09_20_10
Theory : small!categories
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