Related references
Note: Only part of the references are listed.Weak Theories of Concatenation and Arithmetic
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NOTRE DAME JOURNAL OF FORMAL LOGIC (2012)
On Interpretability in the Theory of Concatenation
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Growing Commas. A Study of Sequentiality and Concatenation
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Decidability without mathematics
A Grzegorczyk
ANNALS OF PURE AND APPLIED LOGIC (2004)