PCTeX Talk

I need two things.

1. I need an upside-down capital omega, in straight and in slant. This symbol is standard in group theory, where
\UpsideDownOmega_i (P) is the subgroup of a p-group P consisting of the p^i th powers of its elements. to justify its widespread usage, I need only quote Huppert's "Endliche Gruppen", which is the classic bible of finite group theory.

2. I need extendable up, down, left, right, NE, NW, SE, SW arrows for drawing commutative diagrams of reasonable size where I can fit in symbols on the various arrows. I have done a poor job trying to fit together pieces of arrows and extension bits, but the joins never work properly, and keep shifting. Also, because I am using the symbols at 18pt, they are too thick.

Surely PCTeX can write robust macros for these eight objects, along the lines of the extendable brackets macros that work so well. Then we can use \halign for the commutative diagrams without having to go to either imported diagrams or one of the extremely complicated diagram packages.

Apologies. I forgot to add the further request about harpoon arrows.

3. I also need the four harpoon arrows to be extendable, that is,
\leftrightharpoons, \rightleftharpoons,
\updownharpoons, \downupharpoons.
I expect that that others will want extendable versions of various other arrows. There should be a generic command that extends by a given amount single arrows and double arrows. Such a command could then be applied to a range of arrow types.

The upside down omega is "\mho", (ohm backwards). I don't think there's an italic variant in MT2.

The extensible arrows are part of the "mathtools" package. See http://www.ctan.org/pkg/mathtools for details.

The command \mho works perfectly. Thank you very much, and apologies for my ignorance. An italic version would be useful.

Unfortunately, the mathtools package requires LaTeX, and I am working in plain TeX. It is probably not practical to adapt the package for use outside LaTeX. Do you know of anything else that fits my description? Otherwise, the suggestion for writing such things within MT2 stands.