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  "body": "\n## Summary\n\nIn constructive mathematics, a collection $X$ is **subcountable** if there exists a partial surjection from the natural numbers onto it. This may be expressed as\n\n$$\\exists (I\\subseteq{\\mathbb N}).\\, \\exists f.\\, (f\\colon I\\twoheadrightarrow X),$$\n\nwhere $f\\colon I\\twoheadrightarrow X$ denotes that $f$ is a surjective function from $I$ onto $X$. The surjection is a member of ${\\mathbb N}\\rightharpoonup X$ and here the subclass $I$ of ${\\mathbb N}$ is required to be a set. In other words, all elements of a subcountable collection $X$ are functionally in the image of an indexing set of counting numbers $I\\subseteq{\\mathbb N}$ and thus the set $X$ can be understood as being dominated by the countable set ${\\mathbb N}$.\n",
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