2.1Prove that for
any two semioriented curves with the same code (of the kind introduced
in 3.7) there exists a homeomorphism of 
 which maps one
of them to another  preserving semiorientations.
truein
2.2 Prove that for any two curves 
,
 with the same code of their complex schemes (see Subsection
2.5) there exists a homeomorphism 
 commuting with 
.
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2.3 Deduce 2.7.A and 2.7.B from 2.7.C and, vise versa, 2.7.C from 2.7.A and 2.7.B.