Algorithms of Phase Space Reduction and Asymptotics of Hitting Times for Perturbed Semi-Markov Processes
Pith reviewed 2026-05-25 01:13 UTC · model grok-4.3
The pith
Recurrent algorithms of phase space reduction for regularly and singularly perturbed semi-Markov processes yield conditions for weak convergence of hitting time distributions together with explicit formulas for normalisation functions and a
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The paper claims that new asymptotic recurrent algorithms of phase space reduction for regularly and singularly perturbed semi-Markov processes give effective conditions of weak convergence for distributions and convergence of expectations for hitting times as well as recurrent formulas for computing the corresponding normalisation functions, Laplace transforms for limiting distributions and limits for expectations.
What carries the argument
Asymptotic recurrent algorithms of phase space reduction that operate on the embedded Markov chain and the holding-time distributions of the semi-Markov process.
If this is right
- Effective conditions for weak convergence of the distributions of hitting times are obtained directly from the reduction procedure.
- Convergence of the expectations of hitting times follows from the same conditions.
- Normalisation functions are computed via recurrent relations that avoid inverting large matrices.
- Laplace transforms of the limiting distributions are given by explicit recursive expressions.
- Limits of the expectations are obtained as the output of the final step of the reduction.
Where Pith is reading between the lines
- The recursive structure suggests that the algorithms can be coded once and applied to families of models that differ only in the perturbation parameter.
- Similar reduction steps might be tested on piecewise-deterministic Markov processes or on semi-Markov processes with infinite state spaces.
- The explicit Laplace-transform formulas open the possibility of inverting them numerically to obtain density approximations for moderate time horizons.
- The method could be combined with existing numerical schemes for solving the unperturbed embedded chain when the state space remains large after reduction.
Load-bearing premise
The semi-Markov processes under study must admit regular or singular perturbations for which the required asymptotic conditions on the hitting times hold.
What would settle it
For a concrete regularly perturbed finite-state semi-Markov process, direct Monte Carlo simulation of hitting times that produces a limiting distribution different from the one predicted by the reduction algorithm would falsify the claim.
read the original abstract
The paper presents new asymptotic recurrent algorithms of phase space reduction for regularly and singularly perturbed semi-Markov processes. These algorithms give effective conditions of weak convergence for distributions and convergence of expectations for hitting times as well as recurrent formulas for computing the corresponding normalisation functions, Laplace transforms for limiting distributions and limits for expectations.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript presents new asymptotic recurrent algorithms of phase space reduction for regularly and singularly perturbed semi-Markov processes. These algorithms are claimed to deliver effective conditions of weak convergence for distributions and convergence of expectations for hitting times, together with recurrent formulas for the corresponding normalisation functions, Laplace transforms for limiting distributions, and limits for expectations.
Significance. If the algorithms and attendant convergence statements are rigorously derived, the work would supply a systematic, recurrent method for reducing phase space in perturbed semi-Markov models while furnishing explicit computational formulae; such tools could be valuable in applications requiring asymptotic analysis of hitting times. The emphasis on recurrent formulae is a potential strength for implementability, but the absence of any derivations, explicit conditions, or illustrative examples in the abstract leaves the soundness of the central claims unverified from the available information.
major comments (1)
- Abstract: the abstract asserts the existence of the algorithms and the convergence results but supplies neither derivations nor the precise perturbation assumptions under which the weak-convergence statements hold; without these, the load-bearing claims cannot be assessed.
Simulated Author's Rebuttal
We thank the referee for the report. We address the single major comment below.
read point-by-point responses
-
Referee: Abstract: the abstract asserts the existence of the algorithms and the convergence results but supplies neither derivations nor the precise perturbation assumptions under which the weak-convergence statements hold; without these, the load-bearing claims cannot be assessed.
Authors: Abstracts are concise summaries by design and do not contain derivations or full technical assumptions. The manuscript itself develops the recurrent algorithms for phase-space reduction of regularly and singularly perturbed semi-Markov processes, states the precise perturbation conditions, proves the weak-convergence results for hitting-time distributions and expectations, and supplies the recurrent formulae for normalising functions, Laplace transforms of the limits, and the limiting expectations. revision: no
Circularity Check
No significant circularity detected in derivation chain
full rationale
The paper introduces recurrent asymptotic algorithms for phase-space reduction of regularly and singularly perturbed semi-Markov processes. These algorithms are stated to produce effective conditions for weak convergence of hitting-time distributions, convergence of expectations, and explicit recurrent formulas for normalization functions, Laplace transforms, and limiting expectations. The provided abstract and description contain no quoted equations or steps that reduce by construction to fitted inputs, self-definitions, or load-bearing self-citations. The domain of applicability is explicitly the class of processes admitting the stated perturbations, making the derivation self-contained against external assumptions rather than circular.
Axiom & Free-Parameter Ledger
axioms (1)
- domain assumption The processes are semi-Markov and subject to regular or singular perturbations for which weak convergence and expectation convergence hold under the reduction algorithms.
Reference graph
Works this paper leans on
-
[1]
Alimov, D., Shurenkov, V.M. (1990). Markov renewal theorems in triangular array model. Ukr. Mat. Zh., 42, 1443–1448 (English translation in Ukr. Math. J., 42, 1283–1288)
work page 1990
-
[2]
Alimov, D., Shurenkov, V.M. (1990). Asymptotic behavior of term inating Markov processes that are close to ergodic. Ukr. Mat. Zh., 42, 1701–1703 (English translation in Ukr. Math. J., 42 1535–1538)
work page 1990
-
[3]
Anisimov, V.V. (1971). Limit theorems for sums of random variable s on a Markov chain, connected with the exit from a set that forms a single class in t he limit. Teor. Veroyatn. Mat. Stat., 4, 3–17 (English translation in Theory Probab. Math. Statist., 4, 1–13)
work page 1971
-
[4]
Anisimov, V.V. (1971). Limit theorems for sums of random variable s in array of sequences defined on a subset of states of a Markov chain up to th e exit time. Teor. Veroyatn. Mat. Stat., 4, 18–26 (English translation in Theory Probab. Math. Statist., 4, 15–22)
work page 1971
-
[5]
Anisimov, V.V. (1988). Random Processes with Discrete Compone nts. Vysshaya Shkola and Izdatel’stvo Kievskogo Universiteta, Kiev, 183 pp
work page 1988
-
[6]
Anisimov, V.V. (2008). Switching Processes in Queueing Models. Ap plied Stochastic Methods Series. ISTE, London and Wiley, Hoboken, NJ, 345 pp
work page 2008
-
[7]
Asmussen, S. (1994). Busy period analysis, rare events and tr ansient behavior in fluid flow models. J. Appl. Math. Stoch. Anal., 7, no. 3, 269–299
work page 1994
-
[8]
Asmussen, S. (1997). Phase-type distributions and related po int processes: fitting and recent advances. In: Chakravarthy, S., Attahiru S. Alfa (Ed s.) Matrix-analytic 137 methods in stochastic models. Lecture Notes in Pure and Applied Mat hematics, 183, Dekker, New York, 137–149
work page 1997
-
[9]
Asmussen, S. (2003). Applied Probability and Queues. Second ed ition. Applications of Mathematics, 51, Stochastic Modelling and Applied Probability. Springer, New York, xii+438 pp
work page 2003
-
[10]
Asmussen, S., Albrecher, H. (2010). Ruin Probabilities. Second edition. Advanced Series on Statistical Science & Applied Probability, 14, World Scientific, Hackensack, NJ, xviii+602 pp
work page 2010
-
[11]
Avrachenkov, K.E. (2000). Singularly perturbed finite Markov chains with general ergodic structure. In: Boel, R., Stremersch, G. (Eds.) Discrete E vent Systems. Anal- ysis and Control. Kluwer International Series in Engineering and Com puter Science, 569, Kluwer, Boston, 429–432
work page 2000
-
[12]
Avrachenkov, K.E., Filar, J.A., Howlett, P.G. (2013). Analytic Per turbation Theory and Its Applications. SIAM, Philadelphia, PA, xii+372 pp
work page 2013
-
[13]
Benois, O., Landim, C., Mourragui, M. (2013). Hitting times of rar e events in Markov chains. J. Stat. Phys., 153, no. 6, 967–990
work page 2013
-
[14]
Bini, D.A., Latouche, G., Meini, B. (2005). Numerical Methods for Structured Markov Chains. Numerical Mathematics and Scientific Computation, Oxford Sci- ence Publications, Oxford University Press, New York, xii+327 pp
work page 2005
-
[15]
Borovkov, A.A. (1998). Ergodicity and Stability of Stochastic P rocesses. Wiley Series in Probability and Statistics, 314, Wiley, Chichester, xxiv+585 pp. (Translation from the 1994 Russian original)
work page 1998
-
[16]
Brown, M., Shao, Y. (1987). Identifying coefficients in spectra l representation for first passage-time distributions. Prob. Eng. Inf. Sci., 1 69–74
work page 1987
-
[17]
Cao, W.L., Stewart, W.J. (1985). Iterative aggregation/disag gregation techniques for nearly uncoupled Markov chains. J. Ass. Comp. Mach., 32, 702–719
work page 1985
-
[18]
Darroch, J., Seneta, E. (1965). On quasi-stationary distribu tions in absorbing discrete-time finite Markov chains. J. Appl. Probab., 2, 88–100
work page 1965
-
[19]
Darroch, J., Seneta, E. (1967). On quasi-stationary distribu tions in absorbing continuous-time finite Markov chains. J. Appl. Probab., 4, 192–196
work page 1967
-
[20]
Drozdenko, M. (2007). Weak convergence of first-rare-ev ent times for semi-Markov processes. I. Theory Stoch. Process., 13(29), no. 4, 29–63
work page 2007
-
[21]
Drozdenko, M. (2007). Weak Convergence of First-Rare-Ev ent Times for Semi- Markov Processes. Doctoral dissertation 49, M¨ alardalen University, V¨ aster ˚ as
work page 2007
-
[22]
Drozdenko, M. (2009). Weak convergence of first-rare-ev ent times for semi-Markov processes. II. Theory Stoch. Process., 15(31), no. 2, 99–118
work page 2009
-
[23]
Ele ˘ ıko, Ya.I., Shurenkov, V.M. (1995). Transient phenomena in a class of matrix- valued stochastic evolutions. Teor. ˇImorvirn. Mat. Stat., 52, 72–76 (English transla- tion in Theory Probab. Math. Statist., 52, 75–79)
work page 1995
-
[24]
Englund, E. (2001). Nonlinearly Perturbed Renewal Equations with Applications. Doctoral dissertation, Ume ˚ a University. 138
work page 2001
-
[25]
Englund, E., Silvestrov, D.S. (1997). Mixed large deviation and er godic theorems for regenerative processes with discrete time. In: Jagers, P., Kulldor ff, G., Portenko, N., Silvestrov, D. (Eds.) Proceedings of the Second Scandinavian–Ukr ainian Conference in Mathematical Statistics, Vol. I, Ume ˚ a, 1997. Theory Stoch. Pr ocess., 3(19), no. 1-2, 164–176
work page 1997
-
[26]
Gambin, A., Krzy˙ zanowski, P., Pokarowski, P. (2008). Aggreg ation algorithms for perturbed Markov chains with applications to networks modeling. SI AM J. Sci. Com- put. 31, no. 1, 45–73
work page 2008
-
[27]
Gut, A., Holst, L. (1984). On the waiting time in a generalized roule tte game. Statist. Probab. Lett., 2, no. 4, 229–239
work page 1984
-
[28]
Gyllenberg, M., Silvestrov, D.S. (1994). Quasi-stationary distr ibutions of a stochastic metapopulation model. J. Math. Biol., 33, 35–70
work page 1994
-
[29]
Gyllenberg, M., Silvestrov, D.S. (1999). Quasi-stationary phen omena for semi- Markov processes. In: Janssen, J., Limnios, N. (Eds.) Semi-Marko v Models and Applications. Kluwer, Dordrecht, 33–60
work page 1999
-
[30]
Gyllenberg, M., Silvestrov, D.S. (2000). Nonlinearly perturbed r egenerative processes and pseudo-stationary phenomena for stochastic systems. Sto ch. Process. Appl., 86, 1–27
work page 2000
-
[31]
Gyllenberg, M., Silvestrov, D.S. (2008). Quasi-Stationary Phen omena in Nonlinearly Perturbed Stochastic Systems. De Gruyter Expositions in Mathem atics, 44, Walter de Gruyter, Berlin, ix+579 pp
work page 2008
-
[32]
Hanen, A. (1963). Th´ eor` emes limites pour une suite de cha ˆ ın es de Markov. Ann. Inst. H. Poincar´ e,18, 197–301
work page 1963
-
[33]
(1992) Mean passage times and nearly unco upled Markov chains
Hassin, R., Haviv, M. (1992) Mean passage times and nearly unco upled Markov chains. SIAM J. Disc Math., 5, 386–397
work page 1992
-
[34]
H¨ ossjer, O., Bechly, G., Gauger, A. (2018). Phase-Type Dist ribution Approxima- tions of the Waiting Time Until Coordinated Mutations Get Fixed in a Pop ulation. In: Silvestrov, S., Ran˘ ci´ c, M., Malyarenko, A. (Eds.) Stochastic Processes and Ap- plications, Springer Proceedings in Mathematics & Statistics, 271, Springer, Cham, Chapter 12, 245–314
work page 2018
-
[35]
Kalashnikov, V.V. (1978). Qualitative Analysis of the Behaviour o f Complex Systems by the Method of Test Functions. Series in Theory and Methods of S ystems Analysis, Nauka, Moscow, 247 pp
work page 1978
-
[36]
Kalashnikov, V.V. (1997). Geometric Sums: Bounds for Rare Ev ents with Applica- tions. Mathematics and its Applications, 413, Kluwer, Dordrecht, xviii+265 pp
work page 1997
-
[37]
Kartashov, M.V. (1996). Strong Stable Markov Chains. VSP, U trecht and TBiMC, Kiev, 138 pp
work page 1996
-
[38]
Keilson, J. (1966). A limit theorem for passage times in ergodic re generative pro- cesses. Ann. Math. Statist., 37, 866–870
work page 1966
-
[39]
Keilson, J. (1979). Markov Chain Models – Rarity and Exponentia lity. Applied Math- ematical Sciences, 28, Springer, New York, xiii+184 pp
work page 1979
-
[40]
Kijima, M. (1997). Markov Processes for Stochastic Modelling. Stochastic Modeling Series. Chapman & Hall, London, x+341 pp. 139
work page 1997
-
[41]
Kingman, J.F. (1963). The exponential decay of Markovian tra nsition probabilities. Proc. London Math. Soc., 13, 337–358
work page 1963
-
[42]
Kohlas, J. (1983). Numerical computation of mean passage tim es and absorption probabilities in Markov and semi-Markov models, Zeitschrift Oper. Re s., 30, A197 – A207
work page 1983
-
[43]
Korolyuk, V.S. (1969). On asymptotical estimate for time of a s emi-Markov process being in the set of states. Ukr. Mat. Zh., 21, 842–845
work page 1969
-
[44]
Korolyuk, V.S., Korolyuk, V.V. (1999). Stochastic Models of Sys tems. Mathematics and Its Applications, 469, Kluwer, Dordrecht, xii+185 pp
work page 1999
-
[45]
Koroliuk, V.S., Limnios, N. (2005). Stochastic Systems in Merging Phase Space. World Scientific, Singapore, xv+331 pp
work page 2005
-
[46]
Korolyuk, V., Swishchuk, A. (1995). Semi-Markov Random Evolu tions. Mathematics and Its Applications, 308, Kluwer, Dordrecht, x+310 pp. (English revised edition of Semi-Markov Random Evolutions. Naukova Dumka, Kiev, 1992, 254 p p.)
work page 1995
-
[47]
Korolyuk, V.S., Turbin, A.F. (1970). On the asymptotic behaviou r of the occupation time of a semi-Markov process in a reducible subset of states. Teor . Veroyatn. Mat. Stat., 2, 133–143 (English translation in Theory Probab. Math. Statist., 2, 133–143)
work page 1970
-
[48]
Korolyuk, V.S., Turbin, A.F. (1976). Semi-Markov Processes an d its Applications. Naukova Dumka, Kiev, 184 pp
work page 1976
-
[49]
Korolyuk, V.S., Turbin, A.F. (1978). Mathematical Foundations of the State Lump- ing of Large Systems. Naukova Dumka, Kiev, 218 pp. (English edition : Mathematical Foundations of the State Lumping of Large Systems. Mathematics and its Applica- tions, 264, Kluwer, Dordrecht, 1993, x+278 pp.)
work page 1978
-
[50]
Kovalenko, I.N. (1973). An algorithm of asymptotic analysis of a sojourn time of Markov chain in a set of states. Dokl. Acad. Nauk Ukr. SSR, Ser. A, no. 6, 422–426
work page 1973
-
[51]
Kovalenko, I.N. (1975). Studies in the Reliability Analysis of Comple x Systems. Naukova Dumka, Kiev, 210 pp
work page 1975
-
[52]
Kovalenko, I.N. (1994). Rare events in queuing theory – a surv ey. Queuing Systems Theory Appl., 16, no. 1-2, 1–49
work page 1994
-
[53]
Kovalenko, I.N., Kuznetsov, N.Yu., Shurenkov, V.M. (1996). Mo dels of Random Processes. A Handbook for Mathematicians and Engineers. CRC Pr ess, Boca Raton, FL, 446 pp. (A revised edition of the 1983 Russian original)
work page 1996
-
[54]
Latouche, G. (1991). First passage times in nearly decomposa ble Markov chains. In: Stewart, W.J. (Ed.) Numerical Solution of Markov Chains. Probability : Pure and Applied, 8, Marcel Dekker, New York, 401–411
work page 1991
-
[55]
Latouch, G., Louchard, G. (1978). Return times in nearly deco mposible stochastic processes. J. Appl. Probab., 15, 251–267
work page 1978
-
[56]
Lo` eve, M. (1977). Probability Theory. I. Fourth edition. Gra duate Texts in Mathe- matics, 45, Springer, New York, xvii+425 pp
work page 1977
-
[57]
Masol, V.I., Silvestrov, D.S. (1972). Record values of the occup ation time of a semi- Markov process. Visnik Kiev. Univ., Ser. Mat. Meh., 14, 81–89
work page 1972
-
[58]
Meshalkin, L.D. (1958). Limit theorems for Markov chains with a fi nite number of states. Teor. Veroyatn. Primen., 3, 361–385 (English translation in Theory Probab. Appl., 3, 335–357). 140
work page 1958
-
[59]
Meyn, S.P., Tweedie, R.L. (2009). Markov Chains and Stochastic Stability. Cam- bridge University Press, xxviii+594 pp. (2nd edition of Markov Chains and Stochas- tic Stability. Communications and Control Engineering Series, Spring er, London, 1993, xvi+ 548 pp.)
work page 2009
-
[60]
Ni, Y. (2011). Nonlinearly Perturbed Renewal Equations: Asym ptotic Results and Applications. Doctoral dissertation, 106, M¨ alardalen University, V¨ aster ˚ as
work page 2011
-
[61]
Obzherin, Y.E., Boyko, E.G. (2015). Semi-Markov Models. Contr ol of Restorable Systems with Latent Failures. Elsevier/Academic Press, Amsterda m, xiv+199 pp
work page 2015
-
[62]
Petersson, M. (2016). Perturbed Discrete Time Stochastic M odels. Doctoral disser- tation, Stockholm University
work page 2016
-
[63]
Schweitzer, P.J. (1991). A survey of aggregation-disaggreg ation in large Markov chains. In: Stewart, W.J. (Ed.) Numerical Solution of Markov chains . Probability: Pure and Applied, 8. Marcel Dekker, New York, 63–88
work page 1991
-
[64]
Seneta, E. (1973). Nonnegative Matrices. An Introduction t o Theory and Applica- tions. Wiley, New York, x+214 pp
work page 1973
-
[65]
Seneta, E. (2006). Nonnegative Matrices and Markov chains. Springer Series in Statis- tics, Springer, New York, 2006, xvi+287 pp. (A revised reprint of 2 nd edition of Nonnegative Matrices and Markov Chains. Springer Series in Statist ics. Springer, New York, 1981, xiii+279 pp.)
work page 2006
-
[66]
Shurenkov, V.M. (1980). Transition phenomena of the renewa l theory in asymptotical problems of theory of random processes 1. Mat. Sb ornik, 112, 115–132 (English translation in Math. USSR: Sbornik, 40, no. 1, 107–123 (1981))
work page 1980
-
[67]
Shurenkov, V.M. (1980). Transition phenomena of the renewa l theory in asymptotical problems of theory of random processes 2. Mat. Sb ornik, 112, 226–241 (English translation in Math. USSR: Sbornik, 40, no. 2, 211–225 (1981))
work page 1980
-
[68]
Silvestrov, D.S. (1970). Limit theorems for semi-Markov proce sses and their applica- tions. 1, 2. Teor. Veroyatn. Mat. Stat., 3, 155–172, 173–194 (English translation in Theory Probab. Math. Statist., 3, 159–176, 177–198)
work page 1970
-
[69]
Silvestrov, D.S. (1971). Limit theorems for semi-Markov summa tion schemes. 1. Teor. Veroyatn. Mat. Stat., 4, 153–170 (English translation in Theory Probab. Math. Statist., 4, 141–157)
work page 1971
-
[70]
Silvestrov, D.S. (1974). Limit Theorems for Composite Random F unctions. Vysshaya Shkola and Izdatel’stvo Kievskogo Universiteta, Kiev, 318 pp
work page 1974
-
[71]
Silvestrov, D.S. (1980). Semi-Markov Processes with a Discret e State Space. Library for an Engineer in Reliability, Sovetskoe Radio, Moscow, 272 pp
work page 1980
-
[72]
Silvestrov D.S. (2004). Limit Theorems for Randomly Stopped St ochastic Processes. Probability and Its Applications, Springer, London, xvi+398 pp
work page 2004
-
[73]
Silvestrov D.S. (2014). Improved asymptotics for ruin probab ilities. In: Silvestrov, D., Martin-L¨ of, A. (Eds.) Modern Problems in Insurance Mathemat ics, Chapter 5, EAA series, Springer, Cham, 93–110
work page 2014
-
[74]
Silvestrov, D. (2016). Necessary and sufficient conditions for convergence of first- rare-event times for perturbed semi-Markov processes. Theor . ˘Imovirn. Mat. Stat. 95, 119–137 (Also in Theory Probab. Math. Statist. 95, 135–151) 141
work page 2016
-
[75]
Silvestrov, D. (2018). Individual ergodic theorems for pertu rbed alternating regen- erative processes. In: Silvestrov, S., Ran˘ ci´ c, M., Malyarenko, A. (Eds.) Stochastic Processes and Applications, Chapter 3, Springer Proceedings in Mathematics & Statistics, 271, Springer, Cham, 23–90
work page 2018
-
[76]
Silvestrov, D.S., Drozdenko, M.O. (2006). Necessary and suffic ient conditions for weak convergence of first-rare-event times for semi-Markov pr ocesses. I. Theory Stoch. Process., 12(28), no. 3-4, 151–186
work page 2006
-
[77]
Silvestrov, D.S., Drozdenko, M.O. (2006). Necessary and suffic ient conditions for weak convergence of first-rare-event times for semi-Markov pr ocesses. II. Theory Stoch. Process., 12(28), no. 3-4, 187–202
work page 2006
-
[78]
Silvestrov, D., Silvestrov, S. (2016). Asymptotic expansions f or stationary distri- butions of perturbed semi-Markov processes. In: Silvestrov, S., Ran˘ ci´ c, M. (Eds.) Engineering Mathematics II. Algebraic, Stochastic and Analysis Str uctures for Net- works, Data Classification and Optimization, Chapter 10, Springer Proceedings in Mathematics & Statisti...
work page 2016
-
[79]
Silvestrov, D., Silvestrov, S. (2017). Nonlinearly Perturbed Se mi-Markov Processes. Springer Briefs in Probability and Mathematical Statistics, Springer , Cham, xiv+143 pp
work page 2017
-
[80]
Silvestrov, D., Silvestrov, S. (2017). Asymptotic expansions f or power-exponential moments of hitting times for nonlinearly perturbed semi-Markov pro cesses. Theor. ˘Imovirn. Mat. Stat. 97, 171–187 (Also in Theory Probab. Math. Statist. 97, 183– 200)
work page 2017
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