\Configure{eqn}
\Configure{gather}
Environments of amstex1:
Vmatrix
align*
alignat*
alignat
alignedat
aligned
aligned
align
bmatrix
equation*
equation
gather*
gathered
gather
matrix
multline*
multline
pmatrix
vmatrix
xalignat*
xalignat
xxalignat
-_-_-