about to swap eqnarray to align
changed eqnarray to align in ch4
changed displaymath and eqnarray to align in ch1
changed displaymath and eqnarray to align in ch2
changed displaymath and eqnarray to align in ch3
changed displaymath and eqnarray to align in ch5
changed displaymath and eqnarray to align in ch6
modified some alignment marks
moved new theorems to ch4, moved old theorems to pmin.tex