# Skip Garibaldi

### Applications of motives to Galois cohomology of algebraic groups

**Abstract**: When studying Galois cohomology of semisimple algebraic groups, one often wants to know the fibers of some cohomological invariant. One well-known solution to this kind of problem is Merkurjev's Theorem saying that every quadratic form in $I^2$ with trivial Clifford invariant actually belongs to $I^3$. We describe analogous results for exceptional groups, all proved using motivic techniques but with no motives appearing in the statements.