gistfile1.php

<?php

const ✓ = true;
const ✕ = false;
const ∞ = INF;
const γ = M_EULER;
const π = M_PI;
const e = M_E;

function ≠($left, $right) {
    return $left != $right;
}

function ≅($left, $right) {
    return ($left > $right - 0.0001) && ($left < $right + 0.0001);
}

function ≡($left, $right) {
    return $left === $right;
}

function ≢($left, $right) {
    return $left !== $right;
}

function ∃($value, array $set) {
    return false !== array_search($value, $set, true);
}

function ∄($value, array $set) {
    return false === array_search($value, $set, true);
}

function ∩(array $set1, array $set2) {
    return array_intersect($set1, $set2);
}

function ∪(array $set1, array $set2) {
    return array_merge($set1, $set2);
}

function ⊂(array $subset, array $superset) {
    return $subset == ∩($subset, $superset);
}

function ⊃(array $superset, array $subset) {
    return ⊂($subset, $superset);
}

function ⊄(array $subset, array $superset) {
    return !⊂($subset, $superset);
}

function ⊅(array $superset, array $subset) {
    return !⊂($subset, $superset);
}

function √($value) {
    return sqrt($value);
}

function ∛($value) {
    return pow($value, 1/3);
}

function ∜($value) {
    return pow($value, 1/4);
}

function ≮($left, $right) {
    return $left >= $right;
}

function ≯($left, $right) {
    return $left <= $right;
}

function ≰($left, $right) {
    return $left > $right;
}

function ≱($left, $right) {
    return $left < $right;
}

function ∏() {
    return array_product(func_get_args());
}

function ∑() {
    return array_sum(func_get_args());
}

function ∅() {
    return array();
}