Extended Chebyshev Systems on $( - \infty ,\infty )$
Eli Passow · SIAM Journal on Mathematical Analysis · 1974
Let $0 \leqq t_0 < t_1 < \cdots < t_m $ be a sequence of integers. Necessary and sufficient conditions are obtained for $\{ x^{t_0 } ,x^{t_1 } , \cdots ,x^{t_m } \} $ to form an extended Chebyshev system of order $n + 1$ on $( - \infty ,\infty )$.