For Euclidean space \ textstyle \ textbf { R } ^ d, this is achieved by introducing a locally integrable positive function \ textstyle \ lambda ( x ), where \ textstyle x is a \ textstyle d-dimensional point located in \ textstyle \ textbf { R } ^ d, such that for any bounded region \ textstyle B the ( \ textstyle d-dimensional ) volume integral of \ textstyle \ lambda ( x ) over region \ textstyle B is finite.
