amssymb is necessary for \mathbb

[boltomli]

Error without \usepackage{amssymb}:

! Undefined control sequence.
\MR ->\mathbb 

[yuxtech]

你clone以后再编译一次吧，没有mtpro2的话，确实要加载amssymb，重新修改了18,19,20行，现在已经可以了