“…(Note that although in the latter case L and M are smooth functions, these functions are in fact nearly singular, for t near the endpoints of the parameter interval (0, 2π) for the curve x, and for τ around the corresponding endpoint of the parameter interval for the curve y.) Letting K denote one of the integral kernels L or M in equation (19), in view of the discussion above K may be expressed in the form K(t, τ ) = K 1 (t, τ ) log r 2 (t, τ )+K 2 (t, τ ) for smooth kernels K 1 and K 2 . For a fixed t then, there are two types of integrands for which high-order quadratures must be provided, namely integrands that are smooth in (0, 2π) but have singularities at the endpoints of the interval (that arise from corresponding singularities of the densities φ at the endpoints of the open curves; cf.…”