Let $\mathcal P$ be an arbitrary non-empty set. The elements $A,B,C\ldots \in \mathcal P$ are called **points**.

Let $\mathcal L$ be an arbitrary non-empty set. We call the elements $a,b,c \ldots \in \mathcal L$ **lines**.

Let $\Pi$ be an arbitrary non-empty set. We call the elements $\alpha,\beta,\gamma \ldots \in \Pi$ **planes**.

- Points $\mathcal P$ constitute the
*elements of linear geometry*. - Points $\mathcal P$ and straight lines $\mathcal L$ constitute the
*elements of plane geometry*. - Points $\mathcal P$, straight lines $\mathcal L$, and planes $\Pi$ constitute the
*elements of spacial geometry*.

| | | | | created: 2019-12-21 05:28:01 | modified: 2019-12-21 06:35:34 | by: *bookofproofs* | references: [6260], [8231], [8251], [8324]

(none)

[8231] **Berchtold, Florian**: “Geometrie”, Springer Spektrum, 2017

[8324] **Hilbert, David**: “Grundlagen der Geometrie”, Leipzig, B.G. Teubner, 1903

[8251] **Klotzek, B.**: “Geometrie”, Studienbücherei, 1971

[6260] **Lee, John M.**: “Axiomatic Geometry”, AMC, 2013