On a Lemma of Erdos et al and Its Applications

In 1943, Erdos stated a famous result concerning interpolatory polynomials,but no proof given. Since this theorem is a fundamental and frequently quoted resultof the theory of interpolation, Erdos et al. published a proof in[2] (1989) recently.Three deep lemmas have been established in [2] in order to give this proof. However,we found that the proof of lemma 2 of [2] is not correct. The main purpose of this     

Hermite-Fejer Interpolation With Moved End Points

Let Z_n={z_(kn)=cosθ_(kn):θ_(kn)=(2k-1)/(2n)π,k=1,2…,n}be the zeros of T_n(x)=cosnθ(x=cosθ,θ∈[0,π]).For 0≤ε≤1,let α_n=:α_n(ε)=:cos(1-ε)/(2n)π,β_n=:β_n(ε)=:cos(2n-1+ε)/(2n)π=-α_n,X_n~(1)=(Z_n-{z_(1z)})∪{α_n},X_n~(2)=(Zn-{z_(nn)})∪{β_n},X_n~(3)=(Z_n-{z_(1n),z_(nn)})∪{α_n,β_n},Y_n~(1)=Z_n∪{α_n},Y_n~(2)=Z_n∪{β_n},Y_n~(3)=Z_n∪{α_nβ_n}.