Thread: what does R^R mean where where the R's are bold?

Thanks Toby, you are right that it's technically not a function. But what I really meant is that it certainly does not take its values in R since delta[0]=infinity

what does R^R mean where where the R's are bold? what does R^R mean where where the R's are bold? Specifically I'm looking at the Princeton Review math subject test book, example 6.24 where it asks, "Is the ring R^R an integral domain?"

As pointed out above, the Dirac delta is not a function. It can be thought of as either a distribution (a linear functional on a space of functions) or as a measure on R . What was probably meant instead is the Heaviside step function H , which can be thought of as obtained by integrating the Dirac delta. This function can be defined by H (x)=0 for x<0, and H (x)=1 for x>=0.