We construct an estimator for gravitational potential on an irregular closed surface as a finite spherical polynomial, based on a finite number of sample observations. This estimator is a natural discrete adaptation of an approximation for gravitational potential suggested by Sanso and Sideris. We consider the following discrete analogue of their conjecture: that the error in our estimator is a contraction operator, implying t...

The rise of food security up international political, societal and academic agendas has led to increasing interest in novel means of improving primary food production and reducing waste. There are however, also many ‘post-farm gate’ activities that are critical to food security, including processing, packaging, distributing, retailing, cooking and consuming. These activities all affect a range of important food security elemen...