Skip to main content

All Questions

Filter by
Sorted by
Tagged with
47 votes
1 answer
3k views

A three-line proof of global class field theory?

There is an idea (I think originally due to Tate) that class field theory is fundamentally a consequence of Pontrjagin duality and Hilbert Theorem 90. I'm curious whether this can phrased using modern ...
Dmitry Vaintrob's user avatar
21 votes
3 answers
1k views

The Teichmüller's algebraic interpretation of $H^3$ in group cohomology

In the book "Cohomology of Groups" of Kenneth S. Brown, it is told in the introduction that Teichmüller arrived to $H^3$ in an algebraic context, i.e. that Teichmüller worked with an ...
Josué Tonelli-Cueto's user avatar
4 votes
0 answers
163 views

Problem understanding the cup-products for the modified cohomology in David Harari's book "Galois Cohomology and Class Field Theory"

I'm recently reading the very beginning of David Harari's book Galois Cohomology and Class Field Theory, and I met a problem with the definition of cup-products for the modified cohomology. Before ...
Jianing Song's user avatar