“…The interaction structure is described by second‐order characteristics and can be analysed by using the pair correlation functionwhere λ (2) (·,·) is the second‐order product density function and λ (2) {( u , v ),( s , l )} d( u , v ) d( s , l ) for ( u , v )≠( s , l ) may be interpreted as the probability that there is a point from X in each of the infinitesimal regions around ( u , v ) and ( s , l ) of spatiotemporal volumes d( u , v ) and d( s , l ) respectively (see for example González et al . ()). The process X is called second‐order intensity‐reweighted stationary (SOIRS) iffor any ( u , v ),( s , l ) ∈ W × T , where is some non‐negative function.…”