Function: hgmissymmetrical
Section: hypergeometric_motives
C-Name: hgmissymmetrical
Prototype: lG
Help: hgmissymmetrical(H): is the hypergeometric motive template H symmetrical
 at t=1?
Doc:  is the hypergeometric motive template $H$ symmetrical
 at $t=1$? This means that the $\alpha_{j}$ and $\beta_{k}$ defining the
 template are obtained from one another by adding $1/2$ (modulo $1$), see
 \kbd{hgmtwist}.
 \bprog
 ? H = hgminit([2,2]);
 ? hgmalpha(H)
 %2 = [[1/2, 1/2], [0, 0]]
 ? hgmissymmetrical(H)
 %3 = 1 \\ this template is symmetrical

 ? H = hgminit([5]);
 ? hgmalpha(H)
 %5 = [[1/5, 2/5, 3/5, 4/5], [0, 0, 0, 0]]
 ? hgmissymmetrical(H)
 %6 = 1 \\ this one is not
 @eprog
