The founder of the Institute, Tiberiu Popoviciu, has obtained some outstanding results:

- introduction of the B-spline functions on nonuniform grids, in 1934, (as acknowledged in a paper by C. de Boor and A. Pinkus, and in a subsequent paper of C. de Boor), studied in depth, obtaining the (now called) Marsden recurrence identity from 1970, and the (now called) Boehm’s knot insertion formula, from 1980;
- introduction of the cardinal spline interpolation on arbitrary knots, in 1941, as acknowledged by I.J. Schoenberg himself, in a paper published in Mathematica, in 1968: “In [1941] Popoviciu uses spline functions directly for the purpose for which they are so eminently suited: the approximation of functions. He introduces spline functions of degree
*n*with arbitrary knots…” - first use of the modulus of continuity for obtaining estimations for the remainders in approximation formulas, in 1937;
- prefiguration of the de Casteljau algorithm, by considering the alternative computation of the value of the Bernstein polynomial, in 1937;
- generalization of the Leibniz formula for the product of two functions to divided differences, in 1933;
- introduction and study of the convex functions of higher order, in 1933 and 1945;
- …

**Tiberiu Popoviciu appears in the select History of Approximation Theory (Technion University, Israel).**