@public
def vring(symbols, domain, order=lex):
 _ring = PolyRing(symbols, domain, order)
 pollute([sym.name for sym in _ring.symbols], _ring.gens)
 return _ring

@ public def vring ( symbols , domain , order = lex ) : _ring = PolyRing ( symbols , domain , order ) pollute ( [ sym . name for sym in _ring . symbols ] , _ring . gens ) return _ring
construct a polynomial ring and inject x_1 .