This special issue focuses on recent research in interdisciplinary mathematics and mathematical sciences. For the last four decades, the Forum for Interdisciplinary Mathematics (FIM), a society for researchers in mathematical sciences, has focused on mathematics, combinatorics, statistics, operations research, computer science, fuzzy sets, rough sets, bioinformatics, etc.

The 22nd International Conference of FIM on Interdisciplinary Mathematics, Statistics and Computational Techniques (IMSCT 2013-FIM XXII) was held in Kitakyushu, Japan, on November 10-12, 2013. This conference was organized by the International Society of Management (ISME international), the Graduate School of Information, Production and Systems, Waseda University, in conjunction with FIM. IMSCT 2013-FIM XXII was attended by faculty members, researchers, specialists, and graduate students from around the world.

The 50 papers presented included keynote speeches by Professor Bhu Dev Sharma, Professor Milan Vlach, and Professor Tomonari Suzuki, together with five plenary talks. To promote FIMfs activities, guest editors had also planned to invite public participation in this special issue accepting nine papers, four selected papers from the conference and five papers closely related to this special issue. Each paper underwent strict peer reviews.

The first paper, Crisp and Fuzzy Granular Hierarchical Structures Generated from a Free Monoid, by Tetsuya Murai, Sadaaki Miyamoto, Masahiro Inuiguchi, Yasuo Kudo, and Seiki Akama, proposes a granular hierarchy, and characterizes the mathematical structure based on fuzzy multisets, fuzzy sets, and rough multisets. This granular hierarchy includes Yagerfs fuzzy multisets and Zadehfs fuzzy sets, offering a general framework.

The second paper, Variable Neighborhood Model for Agent Control Introducing Accessibility Relations Between Agents with Linear Temporal Logic, by Seiki Ubukata, Tetsuya Murai, Yasuo Kudo, and Seiki Akama, discusses a variable neighborhood model based on a Kripke framework, and applies this model to introducing the agentfs personal space. The authorsf research is an attempt to realize the agentfs personality.

The third paper, Estimating Writing Neatness from Online Handwritten Data, by Motoki Miura and Takamichi Toda, considers the neatness of handwritten notes in using the authorsf Air-TransNote digital pen technology. The digital pen reports physical information, and authors estimate neatness by using this physical information. Based on experiments, the authors conclude variance in pen speed, average angular point, and average pen speed are the most important features for evaluating handwriting neatness.

The fourth paper, Application of Rough Set-Based Information Analysis to Questionnaire Data, by Naoto Yamaguchi, Mao Wu, Michinori Nakata, and Hiroshi Sakai, applies the authorsf rough non-deterministic information analysis (RNIA) to questionnaire data and question-answering. Experimental results indicate the power of the getRNIA software tool developed by the authors and possibilities for new types of data analysis.

The fifth paper, Analysis of Consistent Equilibria in a Mixed Duopoly, by Vyacheslav V. Kalashnikov, Vladimir A. Bulavsky, Nataliya I. Kalashnykova, Junzo Watada, and Diego Je Jes?s Hern?ndez-Rodr?guez, investigates a model of partially mixed duopoly with conjectured variations in equilibrium. They establish the existence and the uniqueness for conjectured variations in equilibrium for any set of feasible conjectures, and prove the existence theorem for interior equilibrium.

The sixth paper, Mixed Oligopoly: Analysis of Consistent Equilibria, twinned with the fifth paper and by the same authors, deals with a case of an oligopoly. Under condition of the oligopoly, the authors conclude results similar to those of the fifth paper. They also provide numerical experiments illustrating the differences among partially mixed, mixed, and classical oligopoly cases.

The seventh paper, Interest Rate Liberalization and Fiscal Policy in China: A New Keynesian DSGE Model, by Bing Xu, Qiuqin He, Xiaowen Hu, and Shangfeng Zhang, studies the relationships between the liberalization of the interest rate and the fiscal policy in China. The authors propose new Keynesian DSGE analysis, that handles many more factors than the previous model. The new model is applied to analyzing economic data, and the modelfs validity is examined based on experiments.

The eighth paper, Mutually Dependent Markov Decision Processes, by Toshiharu Fujita and Akifumi Kira, investigates dynamic programming and the Markov decision process. The authors propose a new advanced framework, called a mutually dependent Markov decision process. Each process is precisely formulated in dynamic programming style, and simulated by using a numeric example. This paper develops a framework for complex multi-stage decision processes.

The ninth and last paper, Monthly Maximum Accumulated Precipitation Forecasting Using Local Precipitation Data and Global Climate Modes, by Junaida Binti Sulaiman, Herdianti Darwis, and Hideo Hirose, considers the problem of precipitation forecasting in Malaysia, and proposes soft-computing-based analysis methods. In the four methods proposed, multi-neural network-PSO showed the best performance for previous data sets. The development of such an analysis method is expected to make precipitation forecasting more accurate.

In closing, the guest editors would like to acknowledge the efforts of all of the authors for their generous and insightful contributions. We are grateful to the reviewers for their incisive on-time reviews. Profs. P.V. Subrahmanyam, D.S. Hooda, Kalpana K. Mahajan, and Tumulesh Solanky, served as co-chairs and guest editors at IMSCT 2013-FIM XXII, and we acknowledge their invaluable work at this conference. We are grateful to Professors Toshio Fukuda and Kaoru Hirota, Chief Editors of JACIII, for inviting us to serve as Guest Editors of this Journal and to Ms. Reiko Ohta of Fuji Technology Press for her ongoing assistance in the publication of this special issue.