even symmetry
2.By the help of geometric significance of plane or space curve and space surface, and by use of the symmetry of curve and surface to coordinate axis and coordinate surface, how to use the symmetry to calculate the surface integral and curve integral is discussed for the odd (even) functions that are defined on the curve or surface with symmetry.
4.In this paper,the author completely determines the index set of maximum density for the class of ?n? order non?symmetric imprimitive irreducible Boolean matrix with at least one pair of nonzero symmetry entries and whose given period is two. The main results are the following :(ⅰ)if ?n(>3)? is even, then ??H?n=?{2,3,4,5,...,2n-5,2n-4};
5.Although it is possible that new attempts to estimate the vacuum energy density may yield just the right amount to explain cosmic acceleration, many theorists believe that a correct calculation, incorporating a new symmetry principle, will lead to the conclusion that the energy associated with the quantum vacuum is zero. (Even quantum nothingness weighs nothing!
