Zoran Skoda extended Jordanian twist

Borel algebra, Jordanian twist $exp(H\otimes ln (1+\xi E))$

Ogievetsky

$[H, E] = E$

Frobenius algebra, add $A_i,B_i$, extended Jordanian twist

parameters $\alpha_i + \beta_i =1$

$[H,A_i] = \alpha_i A_i$, $[H,B_i] = \beta_i B_i$;

$[E,A_i] = [E,B_j] = 0$

$[A_i,B_j] = \delta_{i j}\gamma_i E$

can have several pairs

$\phi = exp(A \otimes B(1+\xi E)^{-\gamma}) exp(H \otimes ln (1+\xi E)$

Kulish Lyakhovski Mudrov 1995 or so

$\sigma = ln (1+\xi E)$

$\Delta_{\phi}(H) = H\otimes e^{-\sigma}+ 1\otimes H$

lightcone basis kappa Mink $H = M_{+-}$

$E=P_+ = P_0+P_3$

$M_{+a}$, $P_a$