A necessary condition for the hypoellipticity of second-order equations with alternating characteristic form
1984 ◽
Vol 286
(1)
◽
pp. 295-295
Keyword(s):
1987 ◽
Vol 12
(12)
◽
pp. 849-853
1979 ◽
Vol 4
(7)
◽
pp. 701-737
◽
Keyword(s):
1984 ◽
Vol 14
(3)
◽
pp. 549-558
◽
2018 ◽
Vol 2018
(1)
◽
1972 ◽
Vol 39
(1)
◽
pp. 122-124
◽