Description: 4 is a nonnegative integer. (Contributed by Mario Carneiro, 18-Feb-2014)
Ref | Expression | ||
---|---|---|---|
Assertion | 4nn0 | $${\u22a2}4\in {\mathbb{N}}_{0}$$ |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 4nn | $${\u22a2}4\in \mathbb{N}$$ | |
2 | 1 | nnnn0i | $${\u22a2}4\in {\mathbb{N}}_{0}$$ |