▁negative ▁curv ature , ▁Ann als ▁of ▁Mathemat ics ▁ 1 0 5 ▁( 1 9 7 7 ), ▁ 8 1 - 1 0 5 ▁. ▁with ▁R uf us ▁Bow en : ▁Un ique ▁ ▁er god icity ▁ ▁of ▁ ▁hor oc ycle ▁ ▁fol i ations , ▁Israel ▁Journal ▁of ▁Mathemat ics ▁ 2 6 ▁( 1 9 7 7 ) ▁ 4 3 - 6 7 ▁. ▁The ▁hor oc ycle ▁flow ▁is ▁mixing ▁of ▁all ▁degrees , ▁In vent iones ▁Mathemat ica e ▁ 4 6 ▁( 1 9 7 8 ) 2 0 1 - 2 0 9 ▁ ▁with ▁Roy ▁Ad ler : ▁Top ological ▁ ▁entropy ▁ ▁and ▁ ▁equivalence ▁ ▁of ▁ ▁dynam ical ▁ ▁systems , ▁Mem oir s ▁of ▁the ▁American ▁Mathemat ical ▁Society ▁ 2 1 9 ▁( 1 9 7 9 ) ▁. ▁ ▁Top ological ▁conjug acy ▁of ▁hor oc ycle ▁flows , ▁American ▁Journal ▁of ▁Mathemat ics ▁( 1 9 8 3 ) ▁ 6 2 3 - 6 3 2 ▁ ▁with ▁Sel im ▁Tun cel : ▁Ent ropy ▁at ▁a ▁weight - per - symbol ▁and ▁an ▁im bed ding ▁theorem ▁for ▁Mark ov ▁ch ains , ▁ ▁In vent iones ▁Mathemat ica e ▁ 1 0 2 ▁ ▁( 1 9 9 0 ), ▁▁ 2 3 5 - 2 6 6 ▁. ▁with ▁Sel im ▁Tun cel : ▁Mat rices ▁ ▁of ▁ ▁polynomials , ▁ ▁posit ivity , ▁ ▁and ▁ ▁finite