proposition

Proposition 7.3

Bridge-chasing escape

Proposition 7.3 (Bridge-chasing escape). For r≥1r\geq1 and d≥0d\geq0, let Pr,d=Ar(11Ar)d,Ar=02r.P_{r,d}=A_r(11A_r)^d, \qquad A_r=0^{2r}. These are even palindromes. For d>0d>0, λ(Pr,d)=Pr,d−1andbPr,d=1,\lambda(P_{r,d})=P_{r,d-1} \quad\text{and}\quad b_{P_{r,d}}=1, whereas the bridge of ArA_r is 00. The search for the 00-transition from Pr,dP_{r,d} therefore makes exactly dd failed bridge tests before reaching the variable target ArA_r.