Boston Globe management and the Boston Newspaper Guild resumed negotiations Tuesday evening so far apart that the company has proposed, with what it called its "last, best offer," to slash wages of Guild members by about 23 percent to gain the $10 million in additional concessions sought from the union. Following a series of major concessions from the several unions involved, Globe management presented that offer on Sunday, a move that could lay the groundwork for management to declare an impasse and unilaterally impose the draconian wage cuts, said Thomas Kohler, a Boston College law professor. Labor laws allow companies, under certain legal conditions, to impose the conditions of their last, best offers if an impasse is reached in negotiations. This option would almost surely lead to legal challenges and protest, and the argument could be made that management failed to negotiate in good faith.