Note that TeX control sequences can't contain numbers, so what you are actually doing is defining \b with a template that requires it to be followed by 0.
Show that α ∶ Q[X] → Q[X]; p(X) ↦ Xp(X) is an element of E, and that there is β ∈ E such that βα = 1E, but no γ ∈ E such that αγ = 1E.
在texlive.net测试了一下,在LaTeX中直接输入冒号和\colon生成的pdf复制出来的文本都是普通的冒号.
然而在这个PDF Page 8 可以复制出文本Proposition 1.23. Suppose that φ ∶ F → R is a ring homomorphism and R is non-trivial.这个∶就是专门表示ratio的码点, 不是普通的冒号.