( ( The formula ) ( ( is ( written ( in ( terms ( of ( ( the ( vertical ( velocity dispersion ) ) ) ( of ( the ( thin ( disk population ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN formula)) (VP (VBZ is) (VP (VBN written) (PP (IN in) (NP (NP (NNS terms)) (PP (IN of) (NP (NP (DT the) (JJ vertical) (NN velocity) (NN dispersion)) (PP (IN of) (NP (DT the) (JJ thin) (NN disk) (NN population))))))))) (. .)))
The formula is written in terms of the vertical velocity dispersion of the thin disk population.
(ROOT (S (NP (NNP Dispersion)) (VP (VBZ is) (NP (NP (DT the) (NN term)) (PP (IN for) (NP (NP (DT the) (NN spacing)) (PP (IN of) (NP (NP (NNS individuals)) (PP (IN within) (NP (DT a) (NN population))))))))) (. .)))