Polygonia comma Polygonia comma Polygonia comma, the eastern comma, is a North American butterfly in the family Nymphalidae, subfamily Nymphalinae. This butterfly is seasonally variable. The upperside of the summer form's hindwings are all black, whereas the winter forms hindwings are reddish orange. The underside of both forms is striped with dark and light brown. There is a silvery comma mark in the middle of the hindwing in both forms. Its wingspan is . The eastern comma may be spotted in woods near rivers, ponds, marshes, swamps, and other water sources. This butterfly seldom visits flowers, but rather feeds on sap, rotting
Comma category functors out of the product category formula_97. For each comma category there are forgetful functors from it. Several interesting categories have a natural definition in terms of comma categories. Limits and colimits in comma categories may be "inherited". If formula_1 and formula_2 are complete, formula_145 is a continuous, and formula_146 is another functor (not necessarily continuous), then the comma category formula_6 produced is complete , and the projection functors formula_148 and formula_149 are continuous. Similarly, if formula_1 and formula_2 are cocomplete, and formula_152 is cocontinuous, then formula_6 is cocomplete, and the projection functors are cocontinuous. For example, note that in