Coalescence Hidden Variable Fractal Interpolation Functions and its   Smoothness Analysis
  We construct a coalescence hidden variable fractal interpolation function (CHFIF) through a non-diagonal iterated function system(IFS). Such a FIF may be self-affine or non-self-affine depending on the parameters of the defining non-diagonal IFS. The smoothness analysis of the CHFIF has been carried out by using the operator approximation technique. The deterministic construction of functions having order of modulus continuity O (|t|^{delta} (log|t|)^m), (m a non-negative integer and 0 < delta le 1) is possible through our CHFIF. The bounds of fractal dimension of CHFIFs are obtained first in certain critical cases and then, using estimation of these bounds, the bounds of fractal dimension of any FIF are found. 
A. K. B. Chand, G. P. Kapoor (Indian Institute of Technology, Kanpur)