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mjo-algebra: add \alg{} for the subalgebra generated by a set.
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1 %
2 % Abstract algebraic structures.
3 %
4 \ifx\havemjoalgebra\undefined
5 \def\havemjoalgebra{1}
6
7
8 \ifx\operatorname\undefined
9 \usepackage{amsopn}
10 \fi
11
12 % The (sub)algebra generated by its argument, a subset of some ambient
13 % algebra. By definition this is the smallest subalgebra (of the
14 % ambient one) containing that set.
15 \newcommand*{\alg}[1]{\operatorname{alg}\of{{#1}}}
16
17 % The fraction field of its argument, an integral domain. The name
18 % "Frac" was chosen here instead of "Quot" because the latter
19 % corresponds to the term "quotient field," which can be mistaken in
20 % some cases for... a quotient field (something mod something).
21 \newcommand*{\Frac}[1]{\operatorname{Frac}\of{{#1}}}
22
23 % The ideal generated by its argument, a subset consisting of ring or
24 % algebra elements.
25 \newcommand*{\ideal}[1]{\operatorname{ideal}\of{{#1}}}
26
27 % The polynomial ring whose underlying commutative ring of
28 % coefficients is the first argument and whose indeterminates (a
29 % comma-separated list) are the second argumnt.
30 \newcommand*{\polyring}[2]{{#1}\left[{#2}\right]}
31
32
33 \fi