The cheese and specialty shop that has anchored the first floor of the Public Market House in Monument Square for a decade is closing. Kris Horton, owner of K. Horton Specialty Foods, announced on the store’s Facebook page Monday that the store would close and operations of the market “will be handed off to the good people at Karmasouptra,” which occupies an upstairs booth. Horton has owned the specialty shop for 18 years and worked with William Milliken, owner of Maine Beer & Beverage, to open the market space in 2006, when the Portland Public Market, about a block away, closed.