A remark on the positivity of K2

For a number field F, it is proved that the K2-semigroup K2(F,F++) defined in [R.V. Moody, J. Morita, J. Algebra 229 (2000) 1] has similar properties to the positive K2 group K2+(F) introduced by Gras in [J. Number Theory 23 (1986) 322].