Generally, it means regular ellipsis. For example, the sum of arithmetic series 2+4+6+8+10 ...+98+100 represents the sum from 2 to100.

Yes means infinity. For example,/kloc-0 1.555555555…… ... is actually a cycle of 1.55. I couldn't finish writing, so I used ellipsis. It means the same as the dot on the head of 1.5.