All Questions
Tagged with obstruction-theory group-cohomology
2 questions with no upvoted or accepted answers
2
votes
0
answers
117
views
Lazard's $\Gamma_n(f)$ as cocycle
In Michel Lazard's "Commutative Formal Groups" Springer Lecture Notes, he defines an operator on a polynomial 3-cochain $f$ denoted $\Gamma_n(f)$, which defines as the $n^{th}$ homogeneous piece of ...
1
vote
0
answers
161
views
Obstruction to lifting homomorphism of groups
Is there a "cohomology" group that encodes obstructions to constructing a lift in a diagram of groups below? If $X\to Y$ is an extension and the bottom row is the identity map it's just $H^1(...