Nuprl Lemma : groupoid-left-cancellation

∀[G:Groupoid]. ∀[x,y,z:cat-ob(cat(G))]. ∀[a,b:cat-arrow(cat(G)) y z]. ∀[c:cat-arrow(cat(G)) x y].
  uiff((cat-comp(cat(G)) x y z c a) = (cat-comp(cat(G)) x y z c b) ∈ (cat-arrow(cat(G)) x z);a
  = b
  ∈ (cat-arrow(cat(G)) y z))


Proof




Definitions occuring in Statement :  groupoid-cat: cat(G),  groupoid: Groupoid,  cat-comp: cat-comp(C),  cat-arrow: cat-arrow(C),  cat-ob: cat-ob(C),  uiff: uiff(P;Q),  uall: ∀[x:A]. B[x],  apply: f a,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  uiff: uiff(P;Q),  and: P ∧ Q,  uimplies: b supposing a,  prop: ℙ,  true: True,  squash: ↓T,  all: ∀x:A. B[x],  subtype_rel: A ⊆r B,  guard: {T},  iff: P ⇐⇒ Q,  implies: P ⇒ Q
Lemmas referenced :  equal_wf,  cat-arrow_wf,  groupoid-cat_wf,  cat-comp_wf,  and_wf,  cat-ob_wf,  groupoid_wf,  groupoid-inv_wf,  squash_wf,  true_wf,  cat-comp-assoc,  groupoid_inv,  cat-comp-ident,  iff_weakening_equal
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  independent_pairFormation,  hypothesis,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  applyEquality,  hypothesisEquality,  equalitySymmetry,  dependent_set_memberEquality,  applyLambdaEquality,  setElimination,  rename,  productElimination,  sqequalRule,  independent_pairEquality,  isect_memberEquality,  axiomEquality,  because_Cache,  equalityTransitivity,  natural_numberEquality,  lambdaEquality,  imageElimination,  universeEquality,  dependent_functionElimination,  imageMemberEquality,  baseClosed,  independent_isectElimination,  independent_functionElimination

Latex:
\mforall{}[G:Groupoid].  \mforall{}[x,y,z:cat-ob(cat(G))].  \mforall{}[a,b:cat-arrow(cat(G))  y  z].  \mforall{}[c:cat-arrow(cat(G))  x  y].
    uiff((cat-comp(cat(G))  x  y  z  c  a)  =  (cat-comp(cat(G))  x  y  z  c  b);a  =  b)



Date html generated: 2020_05_20-AM-07_55_52
Last ObjectModification: 2017_07_28-AM-09_20_14

Theory : small!categories


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