Chapter Iii - Combination of Two Projectively Related Fundamental Forms

47. Superposed fundamental forms. Self-corresponding elements 48. Special case 49. Fundamental theorem. Postulate of continuity 50. Extension of theorem to pencils of rays and planes 51. Projective point-rows having a self-corresponding point in common 52. Point-rows in perspective position 53. Pencils in perspective position 54. Axial pencils in perspective position 55. Point-row of the second order 56. Degeneration of locus 57. Pencils of rays of the second order 58. Degenerate case 59. Cone of the second order PROBLEMS