giuseppe paleologo paleologogmailcom posed following problemteaser given two matrices come elegant fast short function returns matrix nonduplicated columns matrices column order matter essence matrix equivalent unionxy x vectors could come anything nice ideas giuseppe giuseppe paleologo email paleologogmailcom aol gappy3000 skype gappy3000 gtalk paleologo mobile 9173313497 fact 2325826571 prime alternative html version deleted ______________________________________________ rhelprprojectorg mailing list httpsstatethzchmailmanlistinforhelp please read posting guide httpwwwrprojectorgpostingguidehtml provide commented minimal selfcontained reproducible code wed 06 aug 2008 183243 0400 r union columns two matrices