m C n n
C p m C p ∀m, n, p ∈N, m →Cn n →Cp m →Cp
1C0
0C
0C
0C
C
C
C
p C n n
Pk
i=1 ik
Q1≤k≤nk
Pp
n=1 1
Sn=Pn
k=1 k k n + 1 −k
Sn=n(n+ 1) −Sn
f(x) = Pn
i=0 aixig(x) = Pp
j=0 bjxj
f(x)g(x)
∃k∈N, n = 2k
∀n, p ∈N,∃k, l ∈Nn= 2k p = 2l∃m∈Nn+p= 2m
∀a, b, c ∈C,∃z∈Caz2+bz +c= 0
≤N2(x, y)≤(x0, y0)x=x0y≤y0
∀x, y ∈N(x, y)≤(x, y)
∀x, y, x0, y0∈N(x, y)≤(x0, y0) (x0, y0)≤(x, y)x=x0y=y0
∀x, y, x0, y0, x00, y00 ∈N(x, y)≤(x0, y0) (x0, y0)≤(x00, y00) (x, y)≤(x00, y00)
∀x, y, x0, y0(x, y)≤(x0, y0) (x0, y0)≤(x, y)