Boundedness by 3 of the Whitney Interpolation Constant Original Research Article

Let the function f∈C[0,1] satisfy f(jk−1)=0, j=0,…,k−1. We prove the estimatesupx∈[0,1]∣f(x)∣⩽3 supx,x+kh∈[0,1]∑j=0k(−1)k−jjkf(x+jh) .