We give a rough sketch of the Judaic, Greek, Islamic and Christian positions
in the matter of interest prohibition during the last few millennia and discuss
the way in which interest prohibition is dealt with in Islamic finance, the
problems with authority-based arguments for interest prohibition, and the
prospects of interest prohibition with the advent of electronic money.

Principles of financial product synthesis from a few basic financial products
constitute an interesting research topic inspired by Islamic finance. We make
an effort to answer general questions that should be answered before starting
to investigate the main issues concerning this topic with the formalization of
financial products and principles of financial product synthesis.

We study shedding in the setting of data linkage dynamics, a simple model of
computation that bears on the use of dynamic data structures in programming.
Shedding is complementary to garbage collection. With shedding, each time a
link to a data object is updated by a program, it is determined whether or not
the link will possibly be used once again by the program, and if not the link
is automatically removed. Thus, everything is made garbage as soon as it can be
viewed as garbage. By that, the effectiveness of garbage collection becomes
maximal.

Interaction with services provided by an execution environment forms part of
the behaviours exhibited by instruction sequences under execution. Mechanisms
related to the kind of interaction in question have been proposed in the
setting of thread algebra. Like thread, service is an abstract behavioural
concept. The concept of a functional unit is similar to the concept of a
service, but more concrete. A state space is inherent in the concept of a
functional unit, whereas it is not inherent in the concept of a service.

We develop theory concerning non-uniform complexity in a setting in which the
notion of single-pass instruction sequence considered in program algebra is the
central notion. We define counterparts of the complexity classes P/poly and
NP/poly and formulate a counterpart of the complexity theoretic conjecture that
NP is not included in P/poly. In addition, we define a notion of completeness
for the counterpart of NP/poly using a non-uniform reducibility relation and
formulate complexity hypotheses which concern restrictions on the instruction
sequences used for computation.

Instruction sequences with direct and indirect jump instructions are as
expressive as instruction sequences with direct jump instructions only. We show
that, in the case where the number of instructions is not bounded, there exist
instruction sequences of the former kind from which elimination of indirect
jump instructions is possible without a super-linear increase of their maximal
internal delay on execution only at the cost of a super-linear increase of
their length.