. "\"Any process that activates or increases the frequency, rate or extent of the removal of acetyl groups from histones.\" [GOC:mah]" . . "positive regulation of histone deacetylation" . "up regulation of histone deacetylation" . "up-regulation of histone deacetylation" . "upregulation of histone deacetylation" . . . . "activation of histone deacetylation" . "stimulation of histone deacetylation" .