Hello, I want to write a tensor with either a double overline (or double underline), but the result is not really nice : the gap space between the two lines is too large to me. Is there a way to write double overline/underline which are brought closer ?
An other possibility to me is to write a tensor as a black board letter (with mathbb). Since I use some greek letters, is there a way to make black-board type greek character ? Best regards, JH
