Recent content by andrea.dapor

Ok, problem solved (in Particle Physics): I idiotically thought that if I and C(t) were in G, then also a linear combination such as sI + (1 - s)C(t) would be in G. This is false, since we are talking of a GROUP, not of a linear space! In fact, even sI is not in G (if s is not 1), since its...

Oh, yes! Even sI is not a poincare transformation (if s is not 1, then its determinant is different from 1, that is, it is not a Lorentz transformation). We must build an F just by composing (matrix product) elements of poincare group. Thank you. Ok, but what about this: -split the 2\pi...

(I posted this in Particle Physics too) We call a group G "simply connected" if every curve C(t) in G which is closed (that is, C(0) = C(1) = I) can be continuously deformed into the trivial curve C'(t) = I (where I is the unit element in G). This is formalised saying that, for each closed...

We call a group G "simply connected" if every curve C(t) in G which is closed (that is, C(0) = C(1) = I) can be continuously deformed into the trivial curve C'(t) = I (where I is the unit element in G). This is formalised saying that, for each closed C(t), there exists a continuous function F...