Ruscheweyh–Wirths conjecture on zero-free power-series families
For Λ⊂N∪{0}\Lambda\subset\mathbb N\cup\{0\}Λ⊂N∪{0} and a function fff holomorphic in a domain DDD containing 000, define ⟨f,D⟩∈PΛ\langle f,D\rangle\in P_\Lambda⟨f,D⟩∈PΛ if fff has a power-series expansion ……
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