Analysis suitable T-splines of arbitrary degree

Prof. L. Beirao da Veiga

June 20, 2013, 11 a.m. MT 130

T-splines are nowadays recognized as a promising tool for IGA and have
been the object of recent interest in the literature. In particular,
analysis-suitable (AS) T-splines have emerged: introduced for the
bi-cubic case, they are a sub-class of T-splines for which we have
fundamental mathematical properties needed in a PDE solver, such as
linear independence of the associated blending functions.

Only very recently in the literature T-splines have been extended to
general polynomial degree. In the present talk we study bi-variate
T-spline functions of arbitrary polynomial degrees p and q in the two
coordinate directions. Depending on the odd/even nature of (p,q) the
T-spline blending functions are naturally associated to vertexes, edges
or elements in the (index) mesh.

After a brief review of IGA and defining the T-spline spaces, we
generalize the concept of AS T-splines to arbitrary degree and introduce
the definition of Dual Compatible (DC) T-splines. A space of DC
T-splines enjoys a mathematical structure that, as shown later in the
talk, guarantees a long list of fundamental properties. As one of the
main results here presented we show that AS T-splines of any degree are
also DC, and that the opposite also holds.

Therefore, since the two concepts above are equivalent, by using the DC
structure in the final part of the talk we are able to show that AS
T-splines satisfy (possibly under additional minimal assumptions)
important properties such as linear indipendence, partition of unity,
optimal approximation capabilities, and others.