Contents 1. Introduction 2 2. Preliminaries 4 2.1. Some results on ...

Contents 1. Introduction 2 2. Preliminaries 4 2.1. Some results on ... Contents 1. Introduction 2 2. Preliminaries 4 2.1. Some results on ...

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138Proposition 7.7. In the setting of Theorem 6.29 and Proposition 7.6, there existtwo functorial morphisms σ A : Q ̂Q → A and σ B : ̂QQ → B where σ A is A-bilinearand σ B is B-bilinear and they fulfill(161) σ A ◦ (Ql) = m A ◦ (xA)and(162) σ B ◦ (ν ′ 0Q) = m B ◦ (By) .Moreover the associative conditions hold, that isA µ Q ◦ ( σ A Q ) = µ B Q ◦ ( Qσ B) and B µb Q◦Proof. First we want to prove thatIn fact we have( ) (σ B ̂Q = µ A Q b ◦ ̂QσA).m A ◦ (xA) ◦ (QP x) ◦ ( Qz l P ) = m A ◦ (xA) ◦ (QP x) ◦ (Qz r P ) .m A ◦ (xA) ◦ (QP x) ◦ ( Qz l P ) (102)= x ◦ (χP ) ◦ ( Qz l P )= x ◦ (χP ) ◦ (QP χP ) ◦ (Qδ D P QP ) (128)= x ◦ (χP ) ◦ (χP QP ) ◦ (Qδ D P QP )(130)= x ◦ (χP ) ◦ ( Qε D P QP ) = x ◦ (χP ) ◦ (Qz r P )(102)= m A ◦ (xx) ◦ (Qz r P ) = m A ◦ (xA) ◦ (QP x) ◦ (Qz r P ) .Since Q preserves coequalizers we have(Q ̂Q, Ql) = Coequ Fun((QP x) ◦(Qz l P ) , (QP x) ◦ (Qz r P ) )so that there exists a functorial morphism σ A : Q ̂Q → A which satisfies (161). Nowwe want to show that σ A is A-bilinear that is the following equalities hold( )σ A ◦A µ Q ̂Q = m A ◦ ( Aσ A))σ A ◦(Qµ A Q b = m A ◦ ( σ A A ) .We computem A ◦ ( Aσ A) ◦ (AQl) (161)= m A ◦ (Am A ) ◦ (AxA)m A ass= m A ◦ (m A A) ◦ (AxA) (104)= m A ◦ (xA) ◦ (A µ Q P A )(161)= σ A ◦ (Ql) ◦ (A µ Q P A ) A µ Q= σ A ◦Since AQl is an epimorphism, we get that σ A ◦(A µ Q ̂Q( )A µ Q ̂Q)◦ (AQl) .m A ◦ ( σ A A ) ◦ (QlA) (161)= m A ◦ (m A A) ◦ (xAA)= m A ◦ (Am A ) ◦ (xAA) = x m A ◦ (xA) ◦ (QP m A ))(161)= σ A ◦ (Ql) ◦ (QP m A ) (150)= σ A ◦(Qµ A Q b ◦ (QlA)= m A ◦ ( Aσ A) . We compute

)Since QlA is an epimorphism, we obtain that σ A ◦(Qµ A Q b = m A ◦ ( σ A A ) . Symmetrically,wewant to define σ B . We prove thatIn fact, we havem B ◦ (By) ◦ (yP Q) ◦ ( P w l Q ) = m B ◦ (By) ◦ (yP Q) ◦ (P w r Q) .m B ◦ (By) ◦ (yP Q) ◦ ( P w l Q ) = m B ◦ (yy) ◦ ( P w l Q )(109)= y ◦ (P χ) ◦ ( P w l Q ) = y ◦ (P χ) ◦ (P χP Q) ◦ (P QP δ C Q)(128)= y ◦ (P χ) ◦ (P QP χ) ◦ (P QP δ C Q)(129)= y ◦ (P χ) ◦ ( P QP ε C Q ) = y ◦ (P χ) ◦ (P w r Q)(109)= m B ◦ (yy) ◦ (P w r Q) = m B ◦ (By) ◦ (yP Q) ◦ (P w r Q) .By Lemma ong>2.ong>9, we have(̂QQ, ν′0 Q)= Coequ Fun((yP Q) ◦(P w l Q ) , (yP Q) ◦ (P w r Q) )139so that there exists a functorial morphism σ B : ̂QQ → B which satisfies (162). Nowwe want to show that σ B is B-bicolinear that is the following equalities hold( )σ B ◦B µb QQ = m B ◦ ( Bσ B)m B ◦ ( σ B B ) ( )= σ B ◦ ̂QµBQWe calculatem B ◦ ( Bσ B) ◦ (Bν ′ 0Q) (162)= m B ◦ (Bm B ) ◦ (BBy)m B ass= m B ◦ (m B B) ◦ (BBy) m =Bm B ◦ (By) ◦ (m B P Q)( )(162)= σ B ◦ (ν 0Q) ′ ◦ (m B P Q) (151)= σ B ◦B µb QQ ◦ (Bν 0Q) ′ .( )Since Bν 0Q ′ is an epimorphism, we deduce that σ B ◦B µb QQ = m B ◦ ( Bσ B) . Wecomputem B ◦ ( σ B B ) ◦ (ν ′ 0QB) (162)= m B ◦ (m B B) ◦ (ByB)m B ass= m B ◦ (Bm B ) ◦ (ByB) (108)(162)= σ B ◦ (ν ′ 0Q) ◦ ( BP µ B Q= m B ◦ (By) ◦ ( )BP µ B Q( )̂QµBQ ◦ (ν 0QB) ′ .) ν ′0= σ B ◦Since ν 0QB ′ is an epimorphism, we get that m B ◦ ( σ B B ) = σ B ◦have to prove the associative conditionsA µ Q ◦ ( σ A Q ) = µ B Q ◦ ( Qσ B)( ) (σ B ̂Q = µ A Q b ◦ ̂QσA).B µb Q◦(̂QµBQ). Finally we

)Since QlA is an epimorphism, we obtain that σ A ◦(Qµ A Q b = m A ◦ ( σ A A ) . Symmetrically,wewant to define σ B . We prove thatIn fact, we havem B ◦ (By) ◦ (yP Q) ◦ ( P w l Q ) = m B ◦ (By) ◦ (yP Q) ◦ (P w r Q) .m B ◦ (By) ◦ (yP Q) ◦ ( P w l Q ) = m B ◦ (yy) ◦ ( P w l Q )(109)= y ◦ (P χ) ◦ ( P w l Q ) = y ◦ (P χ) ◦ (P χP Q) ◦ (P QP δ C Q)(128)= y ◦ (P χ) ◦ (P QP χ) ◦ (P QP δ C Q)(129)= y ◦ (P χ) ◦ ( P QP ε C Q ) = y ◦ (P χ) ◦ (P w r Q)(109)= m B ◦ (yy) ◦ (P w r Q) = m B ◦ (By) ◦ (yP Q) ◦ (P w r Q) .By Lemma <str<strong>on</strong>g>2.</str<strong>on</strong>g>9, we have(̂QQ, ν′0 Q)= Coequ Fun((yP Q) ◦(P w l Q ) , (yP Q) ◦ (P w r Q) )139so that there exists a functorial morphism σ B : ̂QQ → B which satisfies (162). Nowwe want to show that σ B is B-bicolinear that is the following equalities hold( )σ B ◦B µb QQ = m B ◦ ( Bσ B)m B ◦ ( σ B B ) ( )= σ B ◦ ̂QµBQWe calculatem B ◦ ( Bσ B) ◦ (Bν ′ 0Q) (162)= m B ◦ (Bm B ) ◦ (BBy)m B ass= m B ◦ (m B B) ◦ (BBy) m =Bm B ◦ (By) ◦ (m B P Q)( )(162)= σ B ◦ (ν 0Q) ′ ◦ (m B P Q) (151)= σ B ◦B µb QQ ◦ (Bν 0Q) ′ .( )Since Bν 0Q ′ is an epimorphism, we deduce that σ B ◦B µb QQ = m B ◦ ( Bσ B) . Wecomputem B ◦ ( σ B B ) ◦ (ν ′ 0QB) (162)= m B ◦ (m B B) ◦ (ByB)m B ass= m B ◦ (Bm B ) ◦ (ByB) (108)(162)= σ B ◦ (ν ′ 0Q) ◦ ( BP µ B Q= m B ◦ (By) ◦ ( )BP µ B Q( )̂QµBQ ◦ (ν 0QB) ′ .) ν ′0= σ B ◦Since ν 0QB ′ is an epimorphism, we get that m B ◦ ( σ B B ) = σ B ◦have to prove the associative c<strong>on</strong>diti<strong>on</strong>sA µ Q ◦ ( σ A Q ) = µ B Q ◦ ( Qσ B)( ) (σ B ̂Q = µ A Q b ◦ ̂QσA).B µb Q◦(̂QµBQ). Finally we

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