time to bury this forever
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2 changed files with 9 additions and 3 deletions
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@ -23,13 +23,17 @@ to, since they're very different concepts.
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>
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> - Does $2$ equal $2$? Yes. This is the same object, and equality is reflexive.
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> - Does $s(s(z))$ equal $2$? Well, typically this is how natural numbers are
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> defined in type systems: $2 \equiv s(s(z))$. _By definition_ they are
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> identical.
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> defined in type systems: $2 \equiv s(s(z))$. If somewhere before this, you
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> said "let $2$ equal $s(s(z))$", then _by definition_ these are identical.
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> - Does $1 + 1$ equal $2$? The operation $+$ is a function, and requires a
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> β-reduction to evaluate any further. This choice really comes down to the
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> choice of the type theory designer; if you wanted a more intensional type
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> theory, you could choose to not allow β-reduction during evaluation of
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> identities. Most type theories _do_ allow this though.
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> - Does $x = y$ for any $x$ and $y$?
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>
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> As far as I understand, you can choose whatever to _be_ your "definitional"
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> equality,
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- **Propositional** equality. This describes a _value_ that potentially holds
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true or false. This is typically written $=$ in math.
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@ -114,4 +118,5 @@ in your language too. In Agda, it's `Path {A} x y`.
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- https://ncatlab.org/nlab/show/definitional+equality
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- https://ncatlab.org/nlab/show/judgment
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- https://ncatlab.org/nlab/show/judgmental+equality
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- https://ncatlab.org/nlab/show/propositional+equality
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- https://hott.github.io/book/hott-ebook.pdf.html
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@ -41,6 +41,7 @@
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$backgroundColor: #202030;
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$textColor: #cdcdcd;
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$linkColor: lightskyblue;
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$linkHoverColor: #202749;
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:root {
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--background-color: #{$backgroundColor};
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@ -53,7 +54,7 @@
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--faded: #666;
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--hr-color: gray;
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--link-color: #{$linkColor};
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--link-hover-color: #{darken($linkColor, 60%)};
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--link-hover-color: #{$linkHoverColor};
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--code-color: #{lighten(firebrick, 25%)};
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--tag-color: #{darken($linkColor, 55%)};
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