<s>
This	O
condition	O
arises	O
frequently	O
in	O
many	O
theorems	O
of	O
functional	B-Application
analysis	I-Application
.	O
</s>
<s>
Unbounded	O
self-adjoint	O
operators	O
on	O
Hilbert	O
spaces	O
are	O
defined	O
on	O
total	B-Algorithm
subsets	I-Algorithm
.	O
</s>
