`deg', `mindeg'
---------------

deg(POLY,VAR)
     :: POLY , ϐ VAR Ɋւō.
mindeg(POLY,VAR)
     :: POLY , ϐ VAR ɊւŒ᎟.

RETURN	
     R
POLY
     
VAR
     s茳

   * ^ꂽ̕ϐ VAR Ɋւō, Œ᎟o͂.
   * ϐ VAR ȗ邱Ƃ͏oȂ.
   * VAR ϐłȂ, VAR ϐ̏ꍇɔrČ.

     [0] deg((x+y+z)^10,x);
     10
     [1] deg((x+y+z)^10,w);
     0
     [75] mindeg(x^2+3*x*y,x);
     1

