(x, y) (x΄, y΄) φ, :
(6)
.
Sxyz SXYZ , (6), . a, w c. , Sxyz SXYZ, (c) Sxy, (a) SXZ, (w) - SoY, Sxyz, SXYZ.
Sxyz SXYZ c, w, a, (6).
1. Sxyz c Sz Sx¢y¢z (. 3.8).
(7)
2. Sx¢y¢z w Sx¢ Sx¢Yz¢ (. 3.8). Sx¢ Sz¢ SXZ, :
(8)
3. Sx¢Yz¢ SY a SXYZ (. 3.8). :
(9)
, , :
, , .
(10)
.
:
(11)
a c, t c¢ SXYZ: SZ t Sx¢y¢Z; Sy¢ a c Sx¢¢y¢z; Sz c¢ Sxyz. , .
(12)
, :
(13)
(14)
a c a .