Abstract: Multiresolution of a polygonal domain consists here in
building a hierarchy of two dimensional unstructured and nested
mesh. Functions are represented on a given level by their mean value on each
triangle and the difference with a value computed by interpolating the mean
values at the coarser level. Data compression is achieved by truncating
these differences with a given tolerance. The notion of hybrid mesh - made of triangles from various resolution levels - is also precisely defined.