Abstract
We propose quantitative measures of wave properties and particle properties for multibeam interferometers. We show that these quantities are connected by a few fundamental inequalities which express wave-particle duality. Our analysis includes which-way detection schemes and quantum erasure. The inequalities derived here are a generalization of similar limits which were studied previously in the special case of two-beam interferometers. In addition, we propose alternative measures that express the available information more efficiently, and we show that these measures fulfill similar inequalities.