nonempty set उदाहरण वाक्य
उदाहरण वाक्य
- Another result analogous to Birkhoff's representation theorem, but applying to a broader class of lattices, is the theorem of that any finite join-distributive lattice may be represented as an antimatroid, a family of sets closed under unions but in which closure under intersections has been replaced by the property that each nonempty set has a removable element.
- In general we must select, for each element of the index set, an element of the nonempty set of limits of the projected ultrafilter base, and of course this uses AC . However, it also shows that the compactness of the product of compact Hausdorff spaces can be proved using ( BPI ), and in fact the converse also holds.
- More generally, if X is a nonempty set and \ lambda is a cardinal, then C \ subseteq [ X ] ^ \ lambda is " club " if every union of a subset of C is in C and every subset of X of cardinality less than \ lambda is contained in some element of C ( see stationary set ).
- In other words, a nonempty set equipped with the proximal relator \ mathcal { R } _ { \ delta _ { \ Phi, \ varepsilon } } has underlying structure provided by the proximal relator \ mathcal { R } _ { \ delta _ { \ Phi } } and provides a basis for the study of tolerance near sets in X that are near within some tolerance.
- If the method is applied to an infinite sequence ( " X " " i " : " i " " ? ) of nonempty sets, a function is obtained at each finite stage, but there is no stage at which a choice function for the entire family is constructed, and no " limiting " choice function can be constructed, in general, in ZF without the axiom of choice.
- Each choice function on a collection " X " of nonempty sets is an element of the family of sets, where a given set can occur more than once as a factor; however, one can focus on elements of such a product that select the same element every time a given set appears as factor, and such elements correspond to an element of the Cartesian product of all " distinct " sets in the family.
- From this bit vector viewpoint, a concrete Boolean algebra can be defined equivalently as a nonempty set of bit vectors all of the same length ( more generally, indexed by the same set ) and closed under the bit vector operations of bitwise'", ( ", and ? as in 1010'" 0110 = 0010, 1010 ( " 0110 = 1110, and ?010 = 0101, the bit vector realizations of intersection, union, and complement respectively.
- The result is an explicit choice function : a function that takes the first box to the first element we chose, the second box to the second element we chose, and so on . ( A formal proof for all finite sets would use the principle of mathematical induction to prove " for every natural number " k ", every family of " k " nonempty sets has a choice function . " ) This method cannot, however, be used to show that every countable family of nonempty sets has a choice function, as is asserted by the axiom of countable choice.
- The result is an explicit choice function : a function that takes the first box to the first element we chose, the second box to the second element we chose, and so on . ( A formal proof for all finite sets would use the principle of mathematical induction to prove " for every natural number " k ", every family of " k " nonempty sets has a choice function . " ) This method cannot, however, be used to show that every countable family of nonempty sets has a choice function, as is asserted by the axiom of countable choice.