['By', 'that', 'we', 'mean', 'that', 'the', 'real', 'part', 'of', 'the', 'Schrödinger', 'equation', 'under', 'polar', 'decomposition', 'of', 'the', 'wave', 'function', 'becomes', 'the', 'classical', 'Hamilton', '–', 'Jacobi', 'equation', 'in', 'the', 'limit', 'where', 'terms', 'involving', 'ℏ', 'are', 'neglected', '.']