U - - (x1,x2...xn),
,
- 1
U.
f(M)=M0(x10, x20,... xn0), M(x1, x2,... xn)
- f(M)=f(x1, x2,... xn)
0,
d() -,
e>0,
| M0M |=d, |f(M)-A|<e
- f(M) - 0,
..
.. -.
limf(x10, x20,... xn0)=limf(x1, x2,... xn)
x10 x1
x20 x2
xn0 xn
2 -
.
- 2 .
2
- Z .
1 :
Z``XX=(Z`x)`x; Z``yy=(Z`y)`y
Z``Xy=(Z`x)`y=(Z`y)`x
- .
