VANCE AND GROMYKO REPORT SOME GAINS IN NEW ARMS TALKS
Sec Vance and Soviet Foreign Min Gromyko rept progress toward resolving issues holding up arms accord, meeting, Geneva; say some difficult problems remain; efforts of US to ensure that USSR does not encode missile test-flight signals to prevent US from monitoring them to verify compliance with accord cited; Vance and Gromyko illus with delegations (M)

