code: function degree(x) {
  
      var i = Number.NEGATIVE_INFINITY;
  
      for (var k in x) {
        if (!FIELD['empty'](x[k]))
          i = Math.max(k, i);
      }
      return i;
    }
docs: Gets the degree of the actual polynomial
  
  @param {Object} x
  @returns {number}