---
res:
bibo_abstract:
- "In two-player finite-state stochastic games of partial obser- vation on graphs,
in every state of the graph, the players simultaneously choose an action, and
their joint actions determine a probability distri- bution over the successor
states. The game is played for infinitely many rounds and thus the players construct
an infinite path in the graph. We consider reachability objectives where the first
player tries to ensure a target state to be visited almost-surely (i.e., with
probability 1) or pos- itively (i.e., with positive probability), no matter the
strategy of the second player.\r\n\r\nWe classify such games according to the
information and to the power of randomization available to the players. On the
basis of information, the game can be one-sided with either (a) player 1, or (b)
player 2 having partial observation (and the other player has perfect observation),
or two- sided with (c) both players having partial observation. On the basis of
randomization, (a) the players may not be allowed to use randomization (pure strategies),
or (b) they may choose a probability distribution over actions but the actual
random choice is external and not visible to the player (actions invisible), or
(c) they may use full randomization.\r\n\r\nOur main results for pure strategies
are as follows: (1) For one-sided games with player 2 perfect observation we show
that (in contrast to full randomized strategies) belief-based (subset-construction
based) strate- gies are not sufficient, and present an exponential upper bound
on mem- ory both for almost-sure and positive winning strategies; we show that
the problem of deciding the existence of almost-sure and positive winning strategies
for player 1 is EXPTIME-complete and present symbolic algo- rithms that avoid
the explicit exponential construction. (2) For one-sided games with player 1 perfect
observation we show that non-elementary memory is both necessary and sufficient
for both almost-sure and posi- tive winning strategies. (3) We show that for the
general (two-sided) case finite-memory strategies are sufficient for both positive
and almost-sure winning, and at least non-elementary memory is required. We establish
the equivalence of the almost-sure winning problems for pure strategies and for
randomized strategies with actions invisible. Our equivalence re- sult exhibit
serious flaws in previous results in the literature: we show a non-elementary
memory lower bound for almost-sure winning whereas an exponential upper bound
was previously claimed.@eng"
bibo_authorlist:
- foaf_Person:
foaf_givenName: Krishnendu
foaf_name: Chatterjee, Krishnendu
foaf_surname: Chatterjee
foaf_workInfoHomepage: http://www.librecat.org/personId=2E5DCA20-F248-11E8-B48F-1D18A9856A87
orcid: 0000-0002-4561-241X
- foaf_Person:
foaf_givenName: Laurent
foaf_name: Doyen, Laurent
foaf_surname: Doyen
bibo_doi: 10.15479/AT:IST-2011-0007
dct_date: 2011^xs_gYear
dct_isPartOf:
- http://id.crossref.org/issn/2664-1690
dct_language: eng
dct_publisher: IST Austria@
dct_title: 'Partial-observation stochastic games: How to win when belief fails@'
...