Tokyo stocks opened mixed Monday, as buying after record highs on Wall Street indexes late last week was offset by selling amid a cautious mood before a vote in parliament to select Japan’s prime minister. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average fell 30.71 points, or 0.08 percent, from Friday to 39,469.66. The broader Topix index was up 6.32 points, or 0.23 percent, at 2,748.47. On the top-tier Prime Market, gainers were led by nonferrous metal and warehousing and harbor transportation service issues, while the top decliners were textile and apparel and chemical …