How do ordinal suffixes work with mathematical constants and other non-Arabic numbers?

Question

This question was inspired by a tweet from the FakeUnicode Twitter account, a semi-novelty account sharing various examples in the wild of bugs, glitches and other unintended results from improperly implementing the Unicode character encoding standard.

What are the English ordinal suffixes of various mathematical constants and concepts? Is it always -th?

πᵗʰ
𝑒ᵗʰ
ℎᵗʰ
𝑖ᵗʰ
φᵗʰ
∞ᵗʰ
ℵ₀ᵗʰ
𝑔₆₄ᵗʰ

[Try saying these aloud for extra fun]
_{source: https://twitter.com/FakeUnicode/status/1086205723736854528}

How does the English language decline ordinal suffixes for numbers that are displayed in a different way than an Arabic number?

Answer 1

In English orthography, there are four ordinal indicators: st, nd, rd for 1, 2, and 3, and th for all the rest, including variables or unreal numbers. Writing the indicator as a superscript, with or without underlining, derives from the practice of Latin scribes.

This is an orthographic convention only loosely connected to the spoken language: whether you can actually pronounce the result, or, when able, you sound like you have a severe lisp, is irrelevant.

One such construction escaped mathematical jargon about as soon as there were enough educated speakers to know what it meant:

…here was beauty—and art—developed to the n’th degree, perfumes, the delicate swish of silk, a being that his arms ached for—and that day passionately clasped. — Gilbert Parker, “The Empty Cruse,” Aspen Evening Chronicle (CO), 23 Mar. 1893.

More contemporary writers simply use nth:

An almost entirely black canvas takes the black square of Malevich to the nth degree. — LA Downtown News, 10 Apr. 2017.

One suspects that had nth yielded as absurd a pronunciation as some of your examples, it never would have made the leap from the classroom into popular language.