Definition 2.1

Let P 𝑃 P italic_P be a smooth manifold and let C ( P ) superscript 𝐶 𝑃 C^{\infty}(P) italic_C start_POSTSUPERSCRIPT ∞ end_POSTSUPERSCRIPT ( italic_P ) be the ring of smooth functions on it. A Leibniz bracket on P 𝑃 P italic_P is a bilinear map [ , ] : C ( P ) × C ( P ) C ( P ) normal-: normal-⋅ normal-⋅ normal-→ superscript 𝐶 𝑃 superscript 𝐶 𝑃 superscript 𝐶 𝑃 [\cdot,\cdot]:C^{\infty}(P)\times C^{\infty}(P)\to C^{\infty}(P) [ ⋅ , ⋅ ] : italic_C start_POSTSUPERSCRIPT ∞ end_POSTSUPERSCRIPT ( italic_P ) × italic_C start_POSTSUPERSCRIPT ∞ end_POSTSUPERSCRIPT ( italic_P ) → italic_C start_POSTSUPERSCRIPT ∞ end_POSTSUPERSCRIPT ( italic_P ) that is a derivation on each entry, that is,

[ f g , h ] = [ f , h ] g + f [ g , h ] and [ f , g h ] = g [ f , h ] + h [ f , g ] , 𝑓 𝑔 𝑓 𝑔 𝑓 𝑔 and 𝑓 𝑔 𝑔 𝑓 𝑓 𝑔 [fg,h]=[f,h]g+f[g,h]\text{\ \ \ and\ \ \ }[f,gh]=g[f,h]+h[f,g], [ italic_f italic_g , italic_h ] = [ italic_f , italic_h ] italic_g + italic_f [ italic_g , italic_h ] and [ italic_f , italic_g italic_h ] = italic_g [ italic_f , italic_h ] + italic_h [ italic_f , italic_g ] ,

for any f , g , h C ( P ) 𝑓 𝑔 superscript 𝐶 𝑃 f,g,h\in C^{\infty}(P) italic_f , italic_g , italic_h ∈ italic_C start_POSTSUPERSCRIPT ∞ end_POSTSUPERSCRIPT ( italic_P ) . We will say that the pair ( P , [ , ] ) 𝑃 normal-⋅ normal-⋅ (P,[\cdot,\cdot]) ( italic_P , [ ⋅ , ⋅ ] ) is a Leibniz manifold . If the bracket [ , ] normal-⋅ normal-⋅ [\cdot,\cdot] [ ⋅ , ⋅ ] is antisymmetric, that is, it satisfies

[ f , g ] = - [ g , f ] 𝑓 𝑔 𝑔 𝑓 [f,g]=-[g,f] [ italic_f , italic_g ] = - [ italic_g , italic_f ]

for every pair of functions f , g C ( P ) 𝑓 𝑔 superscript 𝐶 𝑃 f,g\in C^{\infty}(P) italic_f , italic_g ∈ italic_C start_POSTSUPERSCRIPT ∞ end_POSTSUPERSCRIPT ( italic_P ) then we say that ( P , [ , ] ) 𝑃 normal-⋅ normal-⋅ (P,[\cdot,\cdot]) ( italic_P , [ ⋅ , ⋅ ] ) is an almost Poisson manifold . We will usually denote the almost Poisson brackets with the symbol { , } normal-⋅ normal-⋅ \{\cdot,\cdot\} { ⋅ , ⋅ } .

A function f C ( P ) 𝑓 superscript 𝐶 𝑃 f\in C^{\infty}(P) italic_f ∈ italic_C start_POSTSUPERSCRIPT ∞ end_POSTSUPERSCRIPT ( italic_P ) such that [ f , g ] = 0 𝑓 𝑔 0 [f,g]=0 [ italic_f , italic_g ] = 0 (respectively, [ g , f ] = 0 𝑔 𝑓 0 [g,f]=0 [ italic_g , italic_f ] = 0 ) for any g C ( P ) 𝑔 superscript 𝐶 𝑃 g\in C^{\infty}(P) italic_g ∈ italic_C start_POSTSUPERSCRIPT ∞ end_POSTSUPERSCRIPT ( italic_P ) is called a left (respectively, right ) Casimir of the Leibniz manifold ( P , [ , ] ) 𝑃 normal-⋅ normal-⋅ (P,[\cdot,\cdot]) ( italic_P , [ ⋅ , ⋅ ] ) .


Definition 3

Almost-linear —  Say that an expectation-valued function f 𝑓 f italic_f of possibly several expectation arguments x , y , , z 𝑥 𝑦 𝑧 x,y,\cdots,z italic_x , italic_y , ⋯ , italic_z is almost-linear if it can be written in the form

f . x . y . z = ^ w + g . x + h . y + + i . z , formulae-sequence 𝑓 𝑥 𝑦 ^ 𝑧 𝑤 𝑔 𝑥 𝑦 𝑖 𝑧 f.x.y\cdots.z~{}~{}~{}\mathrel{\hat{=}}~{}~{}~{}w+g.x+h.y+\cdots+i.z~{}, italic_f . italic_x . italic_y ⋯ . italic_z start_RELOP ^ start_ARG = end_ARG end_RELOP italic_w + italic_g . italic_x + italic_h . italic_y + ⋯ + italic_i . italic_z , (21)

where w 𝑤 w italic_w is an expectation and g , h , , i 𝑔 𝑖 g,h,\cdots,i italic_g , italic_h , ⋯ , italic_i are linear expectation-valued functions of their single arguments.


Definition  2.1

[ t 𝑡 t italic_t -Baxter operator] Let t k 𝑡 𝑘 t\in k italic_t ∈ italic_k . Let ( A , ) 𝐴 (A,\ \cdot) ( italic_A , ⋅ ) be an associative algebra. A t 𝑡 t italic_t -Baxter operator is a linear map β : A A : 𝛽 absent 𝐴 𝐴 \beta:A\xrightarrow{}A italic_β : italic_A start_ARROW start_OVERACCENT end_OVERACCENT → end_ARROW italic_A verifying:

β ( x ) β ( y ) = β ( x β ( y ) + β ( x ) y + t x y ) . 𝛽 𝑥 𝛽 𝑦 𝛽 𝑥 𝛽 𝑦 𝛽 𝑥 𝑦 𝑡 𝑥 𝑦 \beta(x)\cdot\beta(y)=\beta(x\cdot\beta(y)+\beta(x)\cdot y+tx\cdot y). italic_β ( italic_x ) ⋅ italic_β ( italic_y ) = italic_β ( italic_x ⋅ italic_β ( italic_y ) + italic_β ( italic_x ) ⋅ italic_y + italic_t italic_x ⋅ italic_y ) .

Definition 5.3 .

Given a positive integer \ell roman_ℓ we define the class subscript {\cal M}_{\ell}\subset{\cal M} caligraphic_M start_POSTSUBSCRIPT roman_ℓ end_POSTSUBSCRIPT ⊂ caligraphic_M of LP- representatives to consist of functions of the form

m ¯ = m m m = ( m ) , fragments ¯ 𝑚 m m m superscript fragments ( m ) , \bar{m}=m\star m\star\ldots\star m=(m\star)^{\ell}, ¯ start_ARG italic_m end_ARG = italic_m ⋆ italic_m ⋆ … ⋆ italic_m = ( italic_m ⋆ ) start_POSTSUPERSCRIPT roman_ℓ end_POSTSUPERSCRIPT ,

for some m 𝑚 m\in{\cal M} italic_m ∈ caligraphic_M .


Definition 1.4 .

Let ( A , δ ) 𝐴 𝛿 (A,\delta) ( italic_A , italic_δ ) be a C * {}^{*} start_FLOATSUPERSCRIPT * end_FLOATSUPERSCRIPT -bialgebra and h h italic_h be a locally finite, lower semicontinuous weight on A 𝐴 A italic_A . We say that h h italic_h is right invariant if for any a A + 𝑎 subscript 𝐴 a\in A_{+} italic_a ∈ italic_A start_POSTSUBSCRIPT + end_POSTSUBSCRIPT such that h ( a ) < 𝑎 h(a)<\infty italic_h ( italic_a ) < ∞ and any φ A + * 𝜑 subscript superscript 𝐴 \varphi\in A^{*}_{+} italic_φ ∈ italic_A start_POSTSUPERSCRIPT * end_POSTSUPERSCRIPT start_POSTSUBSCRIPT + end_POSTSUBSCRIPT we have

h ( φ * a ) = φ ( 1 ) h ( a ) . 𝜑 𝑎 𝜑 1 𝑎 h(\varphi*a)=\varphi(1)h(a). italic_h ( italic_φ * italic_a ) = italic_φ ( 1 ) italic_h ( italic_a ) .
Definition B.1 .

Let B 𝐵 B italic_B be an operator algebra acting on a Hilbert space {\mathcal{H}} caligraphic_H and η 𝜂 \eta italic_η be a (unbounded) linear mapping from B 𝐵 B italic_B into {\mathcal{H}} caligraphic_H . We say that η 𝜂 \eta italic_η is a GNS map if the domain 𝒟 ( η ) 𝒟 𝜂 {\mathcal{D}}(\eta) caligraphic_D ( italic_η ) is a left ideal in B 𝐵 B italic_B and

(B.1) η ( a b ) = a η ( b ) 𝜂 𝑎 𝑏 𝑎 𝜂 𝑏 \eta(ab)=a\eta(b) italic_η ( italic_a italic_b ) = italic_a italic_η ( italic_b )

for any a B 𝑎 𝐵 a\in B italic_a ∈ italic_B and b 𝒟 ( η ) 𝑏 𝒟 𝜂 b\in{\mathcal{D}}(\eta) italic_b ∈ caligraphic_D ( italic_η ) . The GNS map η 𝜂 \eta italic_η is called closed if it is closed with respect to strong operator topology on B 𝐵 B italic_B and norm topology on {\mathcal{H}} caligraphic_H . We say that a GNS map defined on a C * {}^{*} start_FLOATSUPERSCRIPT * end_FLOATSUPERSCRIPT -algebra is densely defined if its domain is norm dense in the C * {}^{*} start_FLOATSUPERSCRIPT * end_FLOATSUPERSCRIPT -algebra. Similarly a GNS map defined on a von Neumann algebra is said to be densely defined if its domain is strongly dense in the von Neumann algebra.


Definition 3 .

Let us consider a higher-order state ρ 𝕊 n ( A ) 𝜌 subscript 𝕊 𝑛 𝐴 \rho\in\mathbb{S}_{n}(A) italic_ρ ∈ blackboard_S start_POSTSUBSCRIPT italic_n end_POSTSUBSCRIPT ( italic_A ) . A projector p A 𝑝 𝐴 p\in A italic_p ∈ italic_A is called ρ 𝜌 \rho italic_ρ -compatible if

(41) ρ ( p ) + ρ ( 1 - p ) = 1 . 𝜌 𝑝 𝜌 1 𝑝 1 \rho(p)+\rho(1-p)=1. italic_ρ ( italic_p ) + italic_ρ ( 1 - italic_p ) = 1 .

The state ρ 𝜌 \rho italic_ρ is called A 𝐴 A italic_A -compatible if the set of all ρ 𝜌 \rho italic_ρ -compatible projectors generates the whole C * superscript 𝐶 C^{*} italic_C start_POSTSUPERSCRIPT * end_POSTSUPERSCRIPT -algebra A 𝐴 A italic_A . Finally, for a given A 𝐴 A italic_A -compatible state ρ 𝜌 \rho italic_ρ , a unital C * superscript 𝐶 C^{*} italic_C start_POSTSUPERSCRIPT * end_POSTSUPERSCRIPT -subalgebra B A 𝐵 𝐴 B\subseteq A italic_B ⊆ italic_A is called ρ 𝜌 \rho italic_ρ -compatible, if ( 40 ) holds for all mutually orthogonal projectors from B 𝐵 B italic_B .


Definition 3.1 .

(cf. [ DW ] ) A symmetric quiver S 𝑆 S italic_S is a quiver endowed with an involution * * * acting on both S 0 subscript 𝑆 0 S_{0} italic_S start_POSTSUBSCRIPT 0 end_POSTSUBSCRIPT and S 1 subscript 𝑆 1 S_{1} italic_S start_POSTSUBSCRIPT 1 end_POSTSUBSCRIPT such that

t ( φ * ) = ( h φ ) * , h ( φ * ) = ( t φ ) * . formulae-sequence 𝑡 superscript 𝜑 superscript 𝜑 superscript 𝜑 superscript 𝑡 𝜑 t(\varphi^{*})=(h\varphi)^{*},h(\varphi^{*})=(t\varphi)^{*}. italic_t ( italic_φ start_POSTSUPERSCRIPT * end_POSTSUPERSCRIPT ) = ( italic_h italic_φ ) start_POSTSUPERSCRIPT * end_POSTSUPERSCRIPT , italic_h ( italic_φ start_POSTSUPERSCRIPT * end_POSTSUPERSCRIPT ) = ( italic_t italic_φ ) start_POSTSUPERSCRIPT * end_POSTSUPERSCRIPT .