# For B-spline what does $\sum_{i=0,n}N_{i,k}(t)=1$ mean?

For B-spline what does $$\sum_{i=0,n}N_{i,k}(t)=1$$ mean?

I don't understand what this means cause $$N_{i,k}(t)$$ are basis functions so what does it mean for them to all sum up to 1?

That means that all the B-Spline basis functions sum to 1 at every $$t$$.