Erasure channel models and bounds. In Chapter 3, we introduce the memoryless erasure channel. The performance limits of the memoryless erasure channel are derived in terms of capacity, as well as in the form of finite-length upper and lower bounds on the block error probability. This chapter continues with a survey of models for erasure channels with memory.

The chapter examines the cultural contact between the Waorani indigenous group and Ecuadorian society that occurred between the years 1950 and 1970. The Waorani are a group of 4,000 hunter-gatherers from the Amazon jungle that remained in voluntary isolation until the arrival of missionaries from the Summer Institute of Linguistics (SIL). Historically, the Waorani were represented as the “other”; the savage with a history of attacking neighboring indigenous people and the nascent Ecuadorian oil industry that wanted to exploit indigenous territories with the support of American evangelists. Among the strategies and consequences of evangelization were population movements, a reduction of enemy tribes in a single territory, infections and deaths from diseases, the expansion of the community’s agricultural and economic frontiers (colonization and extractivist industry), and socioeconomic changes. The Waorani responses reflected a sui generis interpretation of the Christian message that attempted to reconcile distinct universes of meaning and significance. The chapter highlights the recorded testimonies of the first Waorani converts and accounts from SIL missionaries.

In Chapter 11, we address an alternative paradigm for erasure coding that exploits feedback from (multiple) receivers to the transmitter. Here, the receivers are assumed to be interested in the same content, and the transmission takes place over a broadcast channel. The feedback is employed to adapt “on the fly” the coding rate to the channel conditions. This approach, which shares several similarities with the framework of rate-compatible codes with hybrid automatic retransmission query ARQ, relies on the so-called fountain codes. Two well-established classes of fountain codes are discussed, namely the class of LT codes (strongly related to LDPC codes) and the class of Raptor codes.

Here, we present some basic results for random matrices over finite fields.

Weight distribution of LDPC codes: More advanced topics on LDPC codes are covered by Chapter 5, which is focused on structural properties of these codes related to their weight distributions. This chapter addresses weight distributions of unstructured and partially structured LDPC code ensembles as well as weight distribution exponents. It also addresses ensemble expurgation and minimum distance analysis for LDPC codes.

Decoding of LDPC codes on the erasure channel: In Chapter 6, we illustrate different decoding algorithms for LDPC codes over erasure channels, namely, iterative (IT) and maximum likelihood (ML) decoding. Decoding on the erasure channel can be strongly simplified with respect to decoding on other channels, since whenever a symbol is not erased, we know its value with full certainty. We illustrate that iterative decoding can be done by a peeling process which resolves one unknown per iteration. ML decoding can be performed efficiently by solving a sparse system of equations by variants of the Gaussian elimination algorithm.

The primary source at the center of this chapter’s analysis is produced by a Colombian evangelical pioneer and focuses on the expulsion of his family and the evangelical church in the village of La Tulia, Valle, Colombia, in 1949. The autobiographical account, written some years after the event, recounts memories of the experience and its interpretation considering what it meant for him to be an evangelical Christian in Colombia in the mid-twentieth century. The expulsion occurred against the backdrop of a struggle between liberals and conservatives that involved the Catholic Church and the evangelicals, resulting in an unraveling of the social fabric of the communities where the evangelical presence was very important. Pedro Aguirre, author of the text, was the founder of the town of La Tulia, Valle, and a social and liberal leader who, after having supported the construction of the Catholic temple, abandoned Catholicism for Protestantism. The analysis aims to identify the elements at play in the construction of evangelical memories, which will facilitate not only the use of the source itself but also a deeper understanding of the context in which it was produced.

Reflecting on the enduring impact of early Evangelicals in Latin America, the epilogue highlights how nineteenth- and early twentieth-century reformers challenged Catholic dominance and advocated for religious freedom and biblical literacy while also reflecting the biases of their colonial context. It traces the evolution of the region’s religious landscape from Catholic hegemony to one defined by pluralism that was shaped by Evangelical growth, the rising number of religious unaffiliated (“nones”), and shifting church-state relations. It concludes by recognizing that despite these transformations, Latin America remains deeply religious, continuing to express faith as a visible element of identity and public life.

Generalizations of LDPC codes: In Chapter 9, we present code ensembles that may be regarded as special instances, generalization, or modifications of LDPC code ensembles introduced in Chapter 4. This chapter starts with spatially coupled LDPC codes, introduced within a protograph-based framework, then addresses generalized LDPC codes, where some of the CNs impose multiple linear constraints, and finally describes low-density generator matrix codes. Erasure decoding algorithms are described for all code classes.

The 104-year-long Rana regime (1846–1951) prevented writers from writing for lay people, let alone the voices of the marginalized or janajatis, Indigenous people in this context. Writing remained a practice in praise of the Rana regime or the people in power. Literature became the genre belonging to societal elites. Social change through writing became a far cry from reality. Playfulness and freshness in writing – which could be obtained through the voices of the marginalized or through the projection of human relationships and their interactive minds – remained a distant shore. Krishna Lal Subba was imprisoned for nine years for writing a book, Makaiko Kheti (1920), meaning the cultivation of maize (Pandey 2012). Writing was fully censored. It would be a dangerous matter to attempt to write in a regime that did not want the lay people becoming aware and educated, and they always remained as “others” or marginalized. Freedom of literary expression was strictly limited by the Rana government (Hutt 1990). If anyone published a book without the Gorkha Language Publication Committee's approval, the publisher would be fined 50 Nepali rupees, and they would be punished if the book did not meet the Committee's guidelines (Acharya 2022).

However, toward the end of the Rana regime, “some writers had started rejecting the classical conventions of the older tradition, others adapted traditional genres and styles to express new concerns” (Hutt 1990: 5). Laxmi Prasad Devkota's “Muna Madan” (1936) has remained immensely popular over the years, establishing itself as a cornerstone of Nepali literature. It transcends genres, becoming a literary and jhyaure masterpiece, deeply resonating with the masses. Despite its widespread appeal, the content candidly delves into the lives of marginalized communities, shedding light on the “other” and offering a vivid portrayal of society and sociocultural milieu during that era.