I have a simple question about the Gamma function. From the definition of the incomplete Gamma function, the value of the integral should be a positive one. But what I found in Mathematica is that it still pulls out a result for a negative value, without a warning/error message. I try to find more details about the incompleted Gamma function but did not get any information showing that the integral limit can be a negative value. Is there anyone who may let me know why it works for a negative integral limit? Thanks in advance.
