pre_install() {
  /bin/true
}

post_install() {
  echo -- Probably you should install texvc to display math
  /bin/true
}

pre_upgrade() {
  /bin/true
}

post_upgrade() {
  echo -- Probably you should install texvc to display math
  /bin/true
}

pre_remove() {
  /bin/true
}

post_remove() {
  /bin/true
}