<s>
The	O
fluent	B-Application
calculus	I-Application
is	O
a	O
formalism	O
for	O
expressing	O
dynamical	O
domains	O
in	O
first-order	O
logic	O
.	O
</s>
<s>
It	O
is	O
a	O
variant	O
of	O
the	O
situation	B-Application
calculus	I-Application
;	O
the	O
main	O
difference	O
is	O
that	O
situations	O
are	O
considered	O
representations	O
of	O
states	O
.	O
</s>
<s>
The	O
frame	B-Application
problem	I-Application
is	O
solved	O
by	O
asserting	O
that	O
the	O
situation	O
after	O
the	O
execution	O
of	O
an	O
action	O
is	O
identical	O
to	O
the	O
one	O
before	O
but	O
for	O
the	O
conditions	O
changed	O
by	O
the	O
action	O
.	O
</s>
