Lower bounds for spline approximation

Lower Bounds for Approximation by Nonlinear Manifolds

which is the precision to which F approximates K. An instance of classical interest is that in which L is C([0, 1]), K is A"—i.e. those functions bounded by one, and whose modulus of continuity is dominated by the modulus of continuity function o>—and F is the family Pn of polynomials of degree n 1. For this case it is known that there are positive constants A and B, independent of to and n, su...

Lower Bounds and Approximation Guarantees

Some Lower Bounds for Estrada Index

Pointwise error bounds for orthogonal cardinal spline approximation

For orthogonal cardinal spline approximation, closed form expressions of the reproducing kernel and the Peano kernels in terms of exponential splines are proved. Concrete and sharp pointwise error bounds are deduced for low degree splines.

Lower Bounds for Approximation Schemes for Closest String

In the Closest String problem one is given a family S of equal-length strings over some fixed alphabet, and the task is to find a string y that minimizes the maximum Hamming distance between y and a string from S. While polynomial-time approximation schemes (PTASes) for this problem are known for a long time [Li et al.; J. ACM’02], no efficient polynomial-time approximation scheme (EPTAS) has b...