fundamental lemma of variational calculus
1. basic form from wikipedia
- For a continuous function \(f\) on open interval \((a,b)\) if \(\int_a^b f(x)h(x)dx = 0\) for all compactly supported smooth functions \(h\) on \((a,b)\), then \(f\) is identically 0.
- This makes me think of "a vector must be 0 if its dot product with every other vector is 0"