getVariant = function(group, options) {
    var font = options.font;
    if (!font) {
        return null;
    }

    var mode = group.mode;
    if (font === "mathit") {
        return "italic";
    }

    var value = group.value;
    if (utils.contains(["\\imath", "\\jmath"], value)) {
        return null;
    }

    if (symbols[mode][value] && symbols[mode][value].replace) {
        value = symbols[mode][value].replace;
    }

    var fontName = fontMap[font].fontName;
    if (fontMetrics.getCharacterMetrics(value, fontName)) {
        return fontMap[options.font].variant;
    }

    return null;
}
Returns the math variant as a string or null if none is required.