[Music] welcome to syntax a generative introduction fourth edition my name is andrew carney i'm a professor of linguistics at the university of arizona i'm the author of your textbook and i'll be leading you through this series of video tutorials having defined precedence the left to right relationship and dominance the up-down relationship in the tree there are other kinds of relationships between nodes that we might want to characterize in particular we might want to talk about the structural prominence of two items that does not rely upon a dominance relationship so we might want to talk about how prominent something is in the tree that doesn't dominate something else so they're not connected by a line and this is a relationship called c command so we can talk about one item sort of being higher up in the tree than another even when they're not connected by lines and we do this using c command so intuitively c command is the relationship between some node and its sister and all the daughters of its sister so if we look at this tree here you will see that a c commands its sister which is c and all of the daughters of its sisters d e f g h so daughters and granddaughters and so on so a c commands all of those nodes so this is again a structural prominence relationship a is more prominent than all those things but it doesn't rely upon being on top of them in the tree note that it is an um that ah just because one node c commands another doesn't mean that they they say c command each other so for example a does not a c commands d but d does not see command a all right so here's a formal definition a c commands node b if every node dominating a also dominates b and a does not itself dominate b so what does this mean so it means you take um some node you look for its mother and everything else that um its mother dominates is c commanded by it um you cannot don you cannot see command anything that's underneath you so you cannot see command um things you dominate um so the first part of the rule is essentially sisterhood look for sisters and aunt hood so all the things that are daughters and granddaughters of the sister and then you just um can't see command anything that you yourself dominate now this really comes down to two parts one kind is called symmetric c command and symmetric c command amounts to sisterhood so symmetric c command is when a symmetrically c commands uh sorry when a commands b and b commands a so they they c command each other so in our tree here a and b symmetrically c command each other so a c commands b and b c commands a um notice that a does not symmetrically c command d e f g and h those are not sisters okay asymmetric c command is the reverse of that um so uh a asymmetrically c commands b if a c commands b but b does not see command a okay so intuitively these are the cases where we have an ant hood or a great ant hood relationship so a ac you can asymmetrically c commands b e f g and h right because those guys uh do not see command a but a c commands them just as we had a local version of dominance that's immediate dominance and we have a local version of precedence that's immediate precedence we do in fact have a local version of government now it's not called immediate sea command for some reason it's called government which is a traditional term from from grammar from way back but it amounts to being local c command now remember those local government those local dominance and precedence relationships relied upon the notion that if there was nothing intervening between them they were local so with immediate precedence a b g because b intervenes between a and g b that means that a does not immediately precede g this is the same thing here a node governs another node if it c commands it and there's no intervener so there's no need such that there's no node g such that g is c commanded by a and a asymmetrically c commands b now this definition is a little tricky because it turns out that it is what we call relativized so what counts as the intervener can vary so for example when you're looking at two heads the intervener is another head if you're looking at two phrases then the intervener is another phrase so um this is a little more subtle than the other cases so um here we have our tree um and we see that a does not govern b because g intervenes and this is assuming that a g and b are all heads for example so if a g and b are all heads then a governs g g governs b but a does not govern b all right now if g was another category so say g was a phrase then a may well govern b in that circumstance which makes it a little tricky now the good news for you is that we rarely use govern anymore govern was a very popular structural relationship back in the late 1980s and early 90s it was used as a mechanism for indicating what we call licensing relationships those are relationships where you need one item to be in a particular structural configuration with another in order to be grammatical we don't use govern so much anymore but it's good to know what it means because if you ever read any of the older literature in syntax you're going to want to understand what government is so essentially govern is local c command [Music] you