Lemma 5.6

Lemma 5.6 (chunk recursion). Let $P$ be a nonempty even palindrome with suffix link $L=\lambda(P)$, bridge $b$, and bridge block $B_P$. Then $$D_b(P)=L,\qquad \omega_b(P)=B_P,$$ and for every letter $a\ne b$, $$D_a(P)=D_a(L),\qquad \omega_a(P)=\omega_a(L)\,b\,B_P,$$ with the same definedness on both sides (for $L=\epsilon$ the right-hand sides are undefined).