<s>
In	O
computer	B-General_Concept
science	I-General_Concept
,	O
concurrency	B-Application
semantics	I-Application
is	O
a	O
way	O
to	O
give	O
meaning	O
to	O
concurrent	B-Operating_System
systems	I-Operating_System
in	O
a	O
mathematically	O
rigorous	O
way	O
.	O
</s>
<s>
Concurrency	B-Application
semantics	I-Application
is	O
often	O
based	O
on	O
mathematical	O
theories	O
of	O
concurrency	B-Operating_System
such	O
as	O
various	O
process	O
calculi	O
,	O
the	O
actor	B-Application
model	I-Application
,	O
or	O
Petri	B-Operating_System
nets	I-Operating_System
.	O
</s>
<s>
A	O
more	O
detailed	O
account	O
of	O
concurrency	B-Application
semantics	I-Application
is	O
given	O
here	O
:	O
Concurrency	B-Operating_System
(	O
computer	B-General_Concept
science	I-General_Concept
)	O
.	O
</s>
