combinations of argument types, and applied by dis- patching to the most specific matching definition. This model is a good fit for mathematical programming, where it is unnatural for the first argument to "own" all values in Julia are true objects having a type that belongs to a single, fully connected type graph, all nodes of which are equally first-class as types. 120CHAPTER 11. TYPES 121 • There is no meaningful 11.2 Abstract Types Abstract types cannot be instantiated, and serve only as nodes in the type graph, thereby describing sets of related concrete types: those concrete types which are their descendants

combinations of argument types, and applied by dis- patching to the most specific matching definition. This model is a good fit for mathematical programming, where it is unnatural for the first argument to "own" all values in Julia are true objects having a type that belongs to a single, fully connected type graph, all nodes of which are equally first-class as types. 120CHAPTER 11. TYPES 121 • There is no meaningful 11.2 Abstract Types Abstract types cannot be instantiated, and serve only as nodes in the type graph, thereby describing sets of related concrete types: those concrete types which are their descendants

combinations of argument types, and applied by dis- patching to the most specific matching definition. This model is a good fit for mathematical programming, where it is unnatural for the first argument to "own" all values in Julia are true objects having a type that belongs to a single, fully connected type graph, all nodes of which are equally first-class as types. 127CHAPTER 12. TYPES 128 • There is no meaningful 12.2 Abstract Types Abstract types cannot be instantiated, and serve only as nodes in the type graph, thereby describing sets of related concrete types: those concrete types which are their descendants

combinations of argument types, and applied by dis- patching to the most specific matching definition. This model is a good fit for mathematical programming, where it is unnatural for the first argument to "own" all values in Julia are true objects having a type that belongs to a single, fully connected type graph, all nodes of which are equally first-class as types. 127CHAPTER 12. TYPES 128 • There is no meaningful 12.2 Abstract Types Abstract types cannot be instantiated, and serve only as nodes in the type graph, thereby describing sets of related concrete types: those concrete types which are their descendants

combinations of argument types, and applied by dis- patching to the most specific matching definition. This model is a good fit for mathematical programming, where it is unnatural for the first argument to "own" all values in Julia are true objects having a type that belongs to a single, fully connected type graph, all nodes of which are equally first-class as types. 127CHAPTER 12. TYPES 128 • There is no meaningful 12.2 Abstract Types Abstract types cannot be instantiated, and serve only as nodes in the type graph, thereby describing sets of related concrete types: those concrete types which are their descendants

combinations of argument types, and applied by dis- patching to the most specific matching definition. This model is a good fit for mathematical programming, where it is unnatural for the first argument to "own" all values in Julia are true objects having a type that belongs to a single, fully connected type graph, all nodes of which are equally first-class as types. 127CHAPTER 12. TYPES 128 • There is no meaningful 12.2 Abstract Types Abstract types cannot be instantiated, and serve only as nodes in the type graph, thereby describing sets of related concrete types: those concrete types which are their descendants

combinations of argument types, and applied by dis- patching to the most specific matching definition. This model is a good fit for mathematical programming, where it is unnatural for the first argument to "own" all values in Julia are true objects having a type that belongs to a single, fully connected type graph, all nodes of which are equally first-class as types. 127CHAPTER 12. TYPES 128 • There is no meaningful 12.2 Abstract Types Abstract types cannot be instantiated, and serve only as nodes in the type graph, thereby describing sets of related concrete types: those concrete types which are their descendants

combinations of argument types, and applied by dis- patching to the most specific matching definition. This model is a good fit for mathematical programming, where it is unnatural for the first argument to "own" all values in Julia are true objects having a type that belongs to a single, fully connected type graph, all nodes of which are equally first-class as types. 127CHAPTER 12. TYPES 128 • There is no meaningful 12.2 Abstract Types Abstract types cannot be instantiated, and serve only as nodes in the type graph, thereby describing sets of related concrete types: those concrete types which are their descendants

combinations of argument types, and applied by dis- patching to the most specific matching definition. This model is a good fit for mathematical programming, where it is unnatural for the first argument to "own" all values in Julia are true objects having a type that belongs to a single, fully connected type graph, all nodes of which are equally first-class as types. 127CHAPTER 12. TYPES 128 • There is no meaningful 12.2 Abstract Types Abstract types cannot be instantiated, and serve only as nodes in the type graph, thereby describing sets of related concrete types: those concrete types which are their descendants

combinations of argument types, and applied by dis- patching to the most specific matching definition. This model is a good fit for mathematical programming, where it is unnatural for the first argument to "own" all values in Julia are true objects having a type that belongs to a single, fully connected type graph, all nodes of which are equally first-class as types. 127CHAPTER 12. TYPES 128 • There is no meaningful 12.2 Abstract Types Abstract types cannot be instantiated, and serve only as nodes in the type graph, thereby describing sets of related concrete types: those concrete types which are their descendants