It was noted in Systems As Expressions Of Pj Problems that the number of systems is infinite but the number of groups into which systems can be assigned is finite. The 7 existential spaces that constitute this group are as follows:

**Empty Space** (S1)

Empty space implies absence of matter in the space (a void or vacuum). Problems can not be initiated within this space because it has no matter. So, as a system only matter in its surrounding can initiate problems. The containership (e.g area, volume) and identity (e.g. latitude/longitude) of the space are the initial Pj Problems of Interest.

**Single Matter Static Space** (S2)

Everything in the Universe is in motion so there are actually no static spaces in it. Static spaces result from observations relative to frame of references. A frame of reference is basically the background an observer uses to interprete that which is being observed. A space is static relative to a given frame of reference if its position is fixed relative to the frame of reference. Single-Matter Static Space implies just one matter in a static space. Problems can be intiated in this space. All Pj problems except nonquantum grouping/interacting of matter can be of interest in this space.

**Single Matter Dynamic Space** (S3)

This is a single-matter space that is dynamic. A dynamic space is characterized by change relative to a frame of reference. A resultant force is always the cause of the change. A resultant force acting on the matter is responsible for the dynamism. Problems can be intiated in this space. All Pj problems except nonquantum grouping/interacting of matter can be of interest in this space.

**Multi-Matter Static Space** (S4)

A static space containing two or more matter. All the matter are considered together as a collective eventhough each occupies its own static matter-residence. A room where everyone is still and quiet is an example of this space. Problems can be initiated in this space. All the Pj Problems can be of interest in this space.

**Multi-Matter Dynamic Space** (S5)

A dynamic space containing two or more matter. All the matter are considered together as a collective eventhough each matter occupies its own static or dynamic matter-residence. The dynamism of the collective-space is caused by a dynamism in at least one of the matter residencies. A classroom where everyone is still and quiet and only the teacher is speaking is an example of this space. Problems can be initiated in this space. All the Pj Problems can be of interest in this space.

**Multi-Matter Multi-Static Spaces** (S6)

This space is an array of Multi-Matter Static Space (S4). The collective space constituted by a moment of stillness and silence (as in a moment of silent prayer) in every classrooms in a school, is an example of this space. Each classroom with everyone in it still and quiet (S4), is a member of the S6 array. There are many examples of S6 in the inanimate world. Problems can be initiated in this space. All the Pj Problems can be of interest in this space.

**Multi-Matter Multi-Dynamic Spaces** (S7)

This space contains two or more matter, one or more collectives and at least two dynamic spaces in any or all collectives.
A classroom where there are multiple interactions between teacher and pupils or between pupils is an example of S7 with one collective (the classroom). A school with dynamic classrooms of different grades where a classroom form a collective is an example of S7 with multiple collectives. Problems can be initiated in this space. All the Pj Problems can be of interest in this space.

S7 is existentially dominant and the most advanced systems are of type S7. Multi-Matter Multi-Dynamic Spaces in Dynamic Equilbrium (S7P7) are the desired states of existence.