English
The head element of a Hindman finite-product sequence is contained in the Fred's FP set.
Русский
Головной элемент FP последовательности Хиндмана принадлежит множеству FP последовательности.
LaTeX
$$$\\text{head}(a) \\\\in FP(a)$.$$
Lean4
/-- Constructor for `FP`. This is the preferred spelling over `FP.head'`. -/
@[to_additive (attr := match_pattern, nolint defLemma) /--
Constructor for `FS`. This is the preferred spelling over `FS.head'`. -/
]
abbrev head : a.head ∈ FP a :=
FP.head' a