Muntz 1914 + Szasz 1916: span of {x^{lambda_n}} dense in C[0,1] iff sum 1/lambda_n = +inf; density of monomial subseries; basis of nonharmonic approximation.
Muntz 1914 + Szasz 1916: span of {x^{lambda_n}} dense in C[0,1] iff sum 1/lambda_n = +inf; density of monomial subseries; basis of nonharmonic approximation.