I want to find some condition to construct a continuous finitefinitely additive measure on nature. ithe natural numbers, i.e $f:P(N)\rightarrow [0,1]$s.t f({n})=0 $f:P(\mathbb{N})\rightarrow [0,1]$ such that $f(\{n\})=0$,and f and $f$ is an additive measure .
I know in ZFC we can use an untraflter U constractultrafilter $U$ and define $f$ by $f(A)=1\Leftrightarrow A\in U$,but but this is too trival.
How about ZF? or some others conditonother condition?like like large cardinal.