Tom kha kai Dill weed is a common herb which is used in Lao cuisine. The Thais' answer to dill weed (known in Thailand as "phak chi Lao" (), since it is known locally as a Lao herb) in Thai "tom kha" is coriander or cilantro ("phak chi", ). There are other versions of "tom kha kai" made with seafood ("tom kha thale", ), mushrooms ("tom kha het", ), pork ("tom kha mu", ) and tofu ("tom kha taohu", ). In the late 19th century, "tom kha" was not a soup. it was a dish of chicken or duck simmered in a light
Leaf power powers for bounded values of have bounded clique-width, but this is not true of leaf powers with unbounded exponents. A graph is a 2-leaf power if and only if it is the disjoint union of cliques (i.e., a cluster graph). A graph is a 3-leaf power if and only if it is a (bull,dart,gem)-free chordal graph. Based on this characterization and similar ones, 3-leaf powers can be recognized in linear time. Characterizations of 4-leaf powers are given by and , which also enable linear time recognition. For "k" ≥ 5 the recognition problem of "k"-leaf powers is open, and likewise